In Chinese tradition, certain numbers are believed by some to be auspicious (吉利) or inauspicious (不利) based on the Chinese word that the number name sounds similar to. The numbers 0, 6, 8, and 9 are believed to have auspicious meanings because their names sound similar to words that have positive meanings.
The Number 0 (零 or 檸, Pinyin:líng or níng) is a whole number and it is also an even number for the money ends with 0.
The number 2 (二 or 两, Pinyin:èr or liăng) is most often considered a good number in Chinese culture. There is a Chinese saying: "good things come in pairs". It is common to repeat characters in product brand names, such as double happiness, which even has its own character 囍, a combination of two 喜. In Cantonese, two (jyutping: ji6) is homophone of the characters for "easy" (易) and "bright" (亮). In Northern China, the number, when used as an adjective, can also mean "stupid".
The number 3 (三, Pinyin: sān, jyutping: saam1) sounds similar to the character for "birth" (生, Pinyin: shēng, jyutping: saang1), and is considered a lucky number. The number 3 is significant since there are three important stages in a man’s life (birth, marriage and death).
The number 6 also represents wealth in Cantonese, this number is a homophone for (祿 Lok). 6 (六, Pinyin: liù) in Mandarin is pronounced the same as "liu" (溜, Pinyin: liù) and similar to "flow" (流, Pinyin: liú) and is therefore considered good for business.
The number 7 (七, Pinyin: qī) symbolizes "togetherness". It is a lucky number for relationships. It is also recognized as the luckiest number in the West, and is one of the rare numbers that is great in both Chinese and many Western cultures. It is a lucky number in Chinese culture, because it sounds alike to the Chinese word 起 (Pinyin: qǐ) meaning arise, and also 气 (Pinyin: qì) meaning life essence.
Possibly by extension, the number 49, the square of seven, is used in many Chinese folk, Taoist and Buddhist rituals. For example, it is believed[by whom?] that a recently deceased spirit will linger in the living world for 49 days. Therefore a second requiem ritual is often performed at the end of 49 days. Similarly, many rituals require the performer to undergo a 49-day cleansing, fasting, etc.
When named in ritualistic context, the number 49, as the square of seven, is almost always explicitly invoked as "7-7-49" (七七四十九) rather than simply "49".
The word for "eight" (八 Pinyin: bā) sounds similar to the word which means "prosper" or "wealth" (發 – short for "發財", Pinyin: fā). In regional dialects the words for "eight" and "fortune" are also similar, e.g., Cantonese "baat3" and "faat3".
There is also a visual resemblance between two digits, "88", and 囍, the "shuāng xĭ" ("double joy"), a popular decorative design composed of two stylized characters 喜 ("xĭ" meaning "joy" or "happiness").
The number 8 is viewed as such an auspicious number that even being assigned a number with several eights is considered very lucky.
One of Cathay Pacific's flight numbers from Hong Kong to Vancouver and New York is CX888.
Singapore Airlines reserves flight numbers beginning with the number 8 to routes in China and Korea.
SriLankan Airlines reserves flight numbers beginning with the number 8 to routes in China.
In Singapore, a breeder of rare Dragon fish (Asian Arowana) (which are "lucky fish" and being a rare species, are required to be microchipped), makes sure to use numbers with plenty of eights in their microchip tag numbers, and appears to reserve particular numbers especially rich in eights and sixes (e.g., 702088880006688) for particularly valuable specimens.
As part of grand opening promotions, a Commerce Bank branch in New York's Chinatown raffled off safety deposit box No. 888.
An "auspicious" numbering system was adopted by the developers of 39 Conduit Road Hong Kong, where the top floor was "88" – Chinese for double fortune. It is already common in Hong Kong for ~4th floors not to exist; there is no requirement by the Buildings Department for numbering other than that it being "made in a logical order." A total of 43 intermediate floor numbers are omitted from 39 Conduit Road: those missing include 14, 24, 34, 54, 64, all floors between 40 and 49; the floor number which follows 68 is 88.
Similar to the common Western practice of using "9" for price points, it is common to see "8" being used in its place to achieve the same psychological effect. So for example menu prices like $58, $88 are frequently seen.
The number 9 (九, Pinyin: jiŭ, jyutping: gau2), was historically associated with the Emperor of China, and the number was frequently used in matters relating to the Emperor, before the establishment of the imperial examinations officials were organized in the nine-rank system, the nine bestowments were rewards the Emperor made for officials of extraordinary capacity and loyalty, while the nine familial exterminations was one of the harshest punishments the Emperor sentenced; the Emperor's robes often had nine dragons, and Chinese mythology held that the dragon has nine children. It also symbolizes harmony.
Moreover, the number 9 is a homophone of the word for "long lasting" (久), and as such is often used in weddings.
The number 4 is omitted in some Chinese buildings.
Number 4 (四; accounting 肆; pinyinsì) is considered an unlucky number in Chinese because it is nearly homophonous to the word "death" (死 pinyinsǐ). Due to that, many numbered product lines skip the "4": e.g., Nokiacell phones (there is no series beginning with a 4),PalmPDAs, Canon PowerShot G's series (after G3 goes G5), etc. In East Asia, some buildings do not have a 4th floor. (Compare with the Western practice of some buildings not having a 13th floor because 13 is considered unlucky.) In Hong Kong, some high-rise residential buildings omit all floor numbers with "4", e.g., 4, 14, 24, 34 and all 40–49 floors, in addition to not having a 13th floor. As a result, a building whose highest floor is number 50 may actually have only 35 physical floors. Singaporean public transport operator SBS Transit has omitted the number plates for some of its buses whose numbers end with '4' due to this, so if a bus is registered as SBS***3*, SBS***4* will be omitted and the next bus to be registered will be SBS***5*. Note that this only applies to certain buses and not others and that the final asterisk is a checksum letter and not a number. Another Singaporean public transport operator SMRT has omitted the '4' as the first digit of the serial number of the train cars as well as the SMRT Buses NightRider services.
Five (五, pinyin: wǔ, jyutping: ng5) is associated with "not" (Mandarin 無, pinyinwú, and Cantonese 唔 m4). If used for the negative connotation it can become good by using it with a negative. Thus, 54 means "no death". 53 ("ng5 saam1" in Cantonese) sounds like "m4 sang1 （唔生）" – "not live.
Six in Cantonese which has a similar pronunciation to that of "lok6" (落, meaning "to drop, fall, or decline") may form unlucky combinations.
28, 38: As eight means prosperity, twenty eight equates to 'double prosperity', 38 being one of the luckiest, often referred to as 'triple prosperity'.
167, 169, 1679: In Hong Kong, seven (七) and nine (九) both have similar pronunciations to and, respectively, two of "the five most insulting words" in Cantonese – the male genital. Six in Cantonese also has a similar pronunciation to an impolite word which is used to count the number of cylindrical objects. Therefore, 167, 169, 1679 and other creative combinations (such as the infamous taboo "on-9-9") are dirty jokes in Hong Kong culture.
250: In Mandarin, 250 can mean "imbecile" if read in a certain way. 二百五 (èr bǎi wǔ), while literally being a correct way of reading 250 in informal speaking, is usually used to insult someone the speaker considers extremely foolish. Alternative ways such as 兩百五 (lǐang bǎi wǔ) and 二百五十 (èr bǎi wǔ shí) do not have this meaning. There are several different versions of the origin of the use of 250 as an insult, and it is unclear which one is correct.
5354: "不生不死" (m4 saang1 m4 sei2 in Cantonese) sounds like "not alive, not dead". This often refers to something that is half dead or on the verge of death. Also in Cantonese it means improper look.
1314: "一生一世" This sounds like "one life, one lifetime" in both Mandarin and Cantonese, and is often used romantically, akin to "for better, for worse, for richer, for poorer, in sickness and in health, until death do us part" in English.
768: "七六八" (jyutping: cat1 luk6 baat3) rhymes with the phrase "一路發" (jyutping: jat1 lou6 faat3) in Cantonese, which means "fortune all the way." Alternatively, 168 "一六八" is sometimes used for the same term in Mandarin.
7456: In Mandarin, 7456 (qī sì wǔ liù) sounds marginally like "氣死我了" (qì-sǐ wǒ -le, "to make me angry," "to piss me off"), and is sometimes used in internet slang.
9413: "九死一生" (gau2 sei2 yat1 saang1 in Cantonese) – nine die to one live, meaning 90% chance of being dead and only 10% chance of being alive, or survived from such situations (a narrow escape).
521/5211314: In Mandarin it is pronounced wu er yi, it sounds similar to wo ai ni. Which means I love you. 1314: also sounds like forever in Cantonese. yut sung yut sei. which means one life one death in literal terms. Therefore 5211314 means I love you forever.
748: "七四八" In Mandarin this number is pronounced "qī sì bā". If these numbers are stated in certain tones, it has a meaning which roughly translates into: "Why don't you go die?" "去死吧" This combination is more commonly used as an insult to others, or rather, an indirect death threat. Youngsters can jokingly tease each other by saying "你去死吧!". Depending on the mood, place and way of saying this sentence it can confer meanings ranging from joking to insulting or provoking. On the other hand, any 3 digit number that ends with 48 sounds like "wealthy for X live times" (世發) (e.g. 748[七世發] is wealthy for 7 live times"), thus is generally considered lucky, with 448 and 548 being the exceptions since they are also homophones of "死先發"(Wealthy on death) and "唔洗發"(no need/not going to be wealthy).