40 (number)

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394041
Cardinalforty
Ordinal40th
(fortieth)
Factorization23× 5
Divisors1, 2, 4, 5, 8, 10, 20, 40
Roman numeralXL
Latin prefixquadrage-
Binary1010002
Ternary11113
Quaternary2204
Quinary1305
Senary1046
Octal508
Duodecimal3412
Hexadecimal2816
Vigesimal2020
Base 361436
 
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394041
Cardinalforty
Ordinal40th
(fortieth)
Factorization23× 5
Divisors1, 2, 4, 5, 8, 10, 20, 40
Roman numeralXL
Latin prefixquadrage-
Binary1010002
Ternary11113
Quaternary2204
Quinary1305
Senary1046
Octal508
Duodecimal3412
Hexadecimal2816
Vigesimal2020
Base 361436

40 (forty) is the natural number following 39 and preceding 41.

Despite being related to the word "four" (4), 40 is spelled "forty", and not "fourty". The reason is that etymologically (also in accents without the horse–hoarse merger) the words have different vowels.[citation needed] "Forty" containing a contraction in the same way that "fifty" contains a contraction of "five".[citation needed]

In mathematics[edit]

Forty is a composite number, an octagonal number, and as the sum of the first four pentagonal numbers, it is a pentagonal pyramidal number. Adding up some subsets of its divisors (e.g., 1, 4, 5, 10 and 20) gives 40, hence 40 is a semiperfect number.

Given 40, the Mertens function returns 0. 40 is the smallest number n with exactly 9 solutions to the equation φ(x) = n.

Forty is the number of n-queens problem solutions for n = 7.

Since 402 + 1 = 1601 is prime, 40 is a Størmer number.

40 is a repdigit in base 3 (1111) and a Harshad number in base 10.

40 and "The Rule of Three" - If you have a topic which is broken down into three sections,each of these is broken down into three sub-sections and each of these three sub-sections is broken down into a further three sections (three generations using the "rule of three") gives you a total of 40 sections (1+3+9+27).

In science[edit]

Astronomy[edit]

In religion[edit]

The number 40 is used in Jewish, Christian, Islamic, and other Middle Eastern traditions to represent a large, approximate number, similar to "umpteen".

Judaism[edit]

In the Hebrew Bible, forty is often used for time periods, forty days or forty years, which separate "two distinct epochs".[1]

  1. He went up on the seventh day of Sivan, after God gave the Torah to the Jewish people, in order to learn the Torah from God, and came down on the seventeenth day of Tammuz, when he saw the Jews worshiping the Golden Calf and broke the tablets. (Deuteronomy 9:11)
  2. He went up on the eighteenth day of Tammuz to beg forgiveness for the people's sin and came down without God's atonement on the twenty-ninth day of Av. (Deuteronomy 9:25)
  3. He went up on the first day of Elul and came down on the tenth day of Tishrei, the first Yom Kippur, with God's atonement. (Deuteronomy 10:10)

Christianity[edit]

Christianity similarly uses forty to designate important time periods.[1]

Islam[edit]

Yazidism[edit]

Funerary customs[edit]

Hinduism[edit]

In Hindu system some of the popular fasting period consist 40 days and is called the period One 'Mandl kal' Kal means a period and Mandal kal means a period of 40 days. For example the devotees of 'Swami Ayyappa', the name of a Hindu God very popular in Kerala, India ( Sabarimala Swami Ayyappan ) strictly observed forty days fasting and visit ( Only male devotees are permitted to enter into the God's Temple) with their holy submittance or offerings on 41st or a convenient day after a minimum 40 days practice of fasting. The offering is called 'Kanikka'.

Sumerian[edit]

A large number of myths about Enki have been collected from many sites, stretching from Southern Iraq to the Levantine coast. He figures in the earliest extant cuneiform inscriptions throughout the region and was prominent from the third millennium down to Hellenistic times.

The exact meaning of his name is uncertain: the common translation is "Lord of the Earth": the Sumerian en is translated as a title equivalent to "lord"; it was originally a title given to the High Priest; ki means "earth"; but there are theories that ki in this name has another origin, possibly kig of unknown meaning, or kur meaning "mound". The name Ea is allegedly Hurrian in origin while others claim that it is possibly of Semitic origin and may be a derivation from the West-Semitic root *hyy meaning "life" in this case used for "spring", "running water." In Sumerian E-A means "the house of water", and it has been suggested that this was originally the name for the shrine to the God at Eridu.

In sports[edit]

In other fields[edit]

The number on the logo for the American-Japanese hard rock band Crush 40.

Forty is also:

See also[edit]

References[edit]

  1. ^ a b Michael David Coogan, A Brief Introduction to the Old Testament: The Hebrew Bible in Its Context, Oxford, 2008, p. 116
  2. ^ Qur'an 5:25-26
  3. ^ Qur'an 7:142
  4. ^ Qur'an 46:15
  5. ^ Dallal, Tamalyn (2007). 40 Days & 1001 Nights. Seattle: Melati Press. back cover. ISBN 978-0-9795155-0-7. 
  6. ^ "40 Days & 1001 Nights - One Woman's Dance Through Life in the Islamic World". 

Stanley Brandes, Forty:The Age and the Symbol. (Knoxville, Univ of Tennessee Press, 1985)