# 16 (number)

 ← 15 16 17 →
Cardinalsixteen
Ordinal16th
(sixteenth)
Factorization24
Divisors1, 2, 4, 8, 16
Roman numeralXVI
Binary100002
Ternary1213
Quaternary1004
Quinary315
Senary246
Octal208
Duodecimal1412
VigesimalG20
Base 36G36
Hebrewט"ז (Tet Zayin)

"Sixteen" redirects here. For other uses, see Sixteen (disambiguation).
 ← 15 16 17 →
Cardinalsixteen
Ordinal16th
(sixteenth)
Factorization24
Divisors1, 2, 4, 8, 16
Roman numeralXVI
Binary100002
Ternary1213
Quaternary1004
Quinary315
Senary246
Octal208
Duodecimal1412
VigesimalG20
Base 36G36
Hebrewט"ז (Tet Zayin)

16 (sixteen) is the natural number following 15 and preceding 17. 16 is a composite number, and a square number, being 42 = 4 × 4. It is the smallest number with exactly five divisors, its proper divisors being 1, 2, 4 and 8.

In speech, the numbers 16 and 60 are often confused. When carefully enunciated, they differ in which syllable is stressed: 16 vs 60 . However, in dates such as 1666 or when contrasting numbers in the teens, such as 15, 16, 17, the stress shifts to the first syllable: 16 .

Sixteen is the fourth power of two. For this reason, 16 was used in weighing light objects in several cultures. The British have 16 ounces in one pound; the Chinese used to have 16 liangs in one jin. In old days, weighing was done with a beam balance to make equal splits. It would be easier to split a heap of grains into sixteen equal parts through successive divisions than to split into ten parts. Chinese Taoists did finger computation on the trigrams and hexagrams by counting the finger tips and joints of the fingers with the tip of the thumb. Each hand can count up to 16 in such manner. The Chinese abacus uses two upper beads to represent the 5s and 5 lower beads to represent the 1s, the 7 beads can represent a hexadecimal digit from 0 to 15 in each column.

## In mathematics

As a power of 2 it has an aliquot sum one less than itself, 15; and is the fifth composite member of the 3-aliquot tree having the 7 member aliquot sequence (16, 15, 9, 4, 3, 1, 0).

Sixteen is the first number to be the aliquot sum of a lesser number, 12; it is also the aliquot sum of the greater number; the discrete semiprime, 26. It is the fourth power of two.

Sixteen is the only integer that equals mn and nm, for some unequal integers m and n (m = 4, n = 2, or vice versa). It has this property because 22 = 2 × 2. It is also equal to 32 (see tetration).

15 and 16 form a Ruth–Aaron pair under the second definition in which repeated prime factors are counted as often as they occur.

Since it is possible to find sequences of 16 consecutive integers such that each inner member shares a factor with either the first or the last member, 16 is an Erdős–Woods number. The smallest such range of 16 consecutive integers is from 2184 to 2200.[1]

In bases 20, 24 and 30, sixteen is a 1-automorphic number (displayed as the numeral 'G').

16 is a centered pentagonal number

16 is the base of the hexadecimal number system, which is used extensively in computer science

16 appears in the Padovan sequence, preceded by the terms 7, 9, 12 (it is the sum of the first two of these)

## Age 16

• Sixteen is the minimum age for being allowed an official beginners driver's license with parental consent in many U.S. states and in Canada. In Australia, Iceland, Norway and the Isle of Man, it is the age one can begin to get a learner's license
• In some states in the U.S, and some provinces in Canada, it is the age one can obtain a learner's permit
• Sixteen is the minimum age for getting an adult job in most states and provinces across the globe
• Sixteen is the minimum age that one can drop out of school in most states of the US (however, restrictions apply and vary depending on state)
• In the United States, female 16-year-olds earn the right to privacy laws surrounding OBGYN practices
• In Belgium, Switzerland and Italy, it is the legal minimum age for a person to purchase any tobacco product
• In the United States, 16 is the most common age of sexual consent, as well as in the United Kingdom.[2][3]
• For its "coming of age" significance, this age has inspired the titles of many songs, such as "Happy Birthday Sweet Sixteen", "You're Sixteen", "Sweet Sixteen", "U16 Girls" "Sweet Little Sixteen" and "Sixteen Candles"
• Sixteen is the minimum age to get married with parental consent in many countries and without parental consent in Scotland
• Sixteen is the legal drinking age in Germany, Belgium, Switzerland, Austria, Italy and Portugal
• In the Netherlands, 16 is the age when all adult rights are granted, but the age of majority is 18
• Minimum age at which one can buy, rent, purchase, buy tickets to, or view a 16+ rated movie in the province of Quebec. It is also the minimum age at which one can accompany a minor under 13 while buying, renting, or purchasing tickets to a 13+ rated movie in the province of Quebec
• Minimum age at which one can donate blood with parental consent in many states
• Minimum age at which one can obtain a 10-year passport in the United States, United Kingdom and Australia
• Minimum age at which one can join the Armed Forces in the United Kingdom (deployment is only allowed at 18)
• Voting age in the Isle of Man, Austria and Nicaragua, and during the 19th century, in the Transvaal Republic

## In sports

### American football

• The number of regular-season games that each NFL team currently plays

### Association football

• The number of teams that qualified for the finals of the FIFA World Cup from 1934 through 1978 (although for various reasons, only 15 competed in the 1938 and 1950 finals)
• The number of teams that qualified for the finals of the FIFA Women's World Cup from 1999 through 2011

### Auto racing

• The number of a car in the NASCAR Sprint Cup Series.run by Roush Fenway Racing and its predecessor, Roush Racing, from 1992–2000 and 2002–present. Since the car's return to the Cup Series, it has been driven by Greg Biffle.
• As of the 2014 season, the number of drivers that qualify for NASCAR's season-ending Chase for the Sprint Cup.

### Rugby union

• Since adopting its current 15-team format in 2011, Super Rugby has conducted a 16-game regular season.

## In other fields

Sixteen frames of images