16 (number)

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← 15 16 17 →
Numeral systemhexadecimal
Divisors1, 2, 4, 8, 16
Greek numeralΙϚ´
Roman numeralXVI
Hebrew numeralט"ז / י"ו
Babylonian numeral𒌋𒐚

16 (sixteen) is the natural number following 15 and preceding 17. It is the fourth power of two.

In English speech, the numbers 16 and 60 are sometimes confused, as they sound very similar.


16 is the ninth composite number, and a square number: 42 = 4 × 4 (the first non-unitary fourth-power prime of the form p4). It is the smallest number with exactly five divisors, its proper divisors being 1, 2, 4 and 8.

Sixteen is the only integer that equals mn and nm, for some unequal integers m and n (, , or vice versa).[1] It has this property because . It is also equal to 32 (see tetration).

The aliquot sum of 16 is 15, within an aliquot sequence of four composite members (16, 15, 9, 4, 3, 1, 0) that belong to the prime 3-aliquot tree.

  • Sixteen is the largest known integer n, for which is prime.
  • It is the first Erdős–Woods number.[2]
  • There are 16 partially ordered sets with four unlabeled elements.[3]

16 is the only number that can be both the perimeter and area of the same square, due to being equal to


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



Group 16 of the periodic table are the chalcogens. 16 is the atomic number of sulfur.


  • There are 16 different personality types in the Myers–Briggs classification system.
  • The amount of waking hours in a day in an "8 hours of sleep" schedule is 16



As a unit of measurement[edit]

A low power of two, 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[vague], 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.

Age 16[edit]

Other fields[edit]


  1. ^ David Wells (1987). The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books. p. 93.
  2. ^ "Sloane's A059756 : Erdős–Woods numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 4 December 2020.
  3. ^ Sloane, N. J. A. (ed.). "Sequence A000112 (Number of partially ordered sets (posets) with n unlabeled elements)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  4. ^ "Age of Consent By State". Archived from the original on 17 April 2011.
  5. ^ "Age of consent for sexual intercourse". Avert. Archived from the original on 22 April 2011.

External links[edit]