14 (fourteen) is the natural number following 13 and preceding 15.

In mathematics

Fourteen is a composite number, its proper divisors being 1, 2 and 7.

In base fifteen and higher bases (such as hexadecimal), fourteen is represented as E.

Fourteen is the sum of the first three squares, which makes it a square pyramidal number.

This number is the lowest even n for which the equation φ(x) = n has no solution, making it the first even nontotient (see Euler's totient function). It is a Catalan number.

Take a set of real numbers and apply the closure and complement operations to it in any possible sequence. At most 14 distinct sets can be generated in this way. This holds even if the reals are replaced by a more general topological space.

Fourteen is a Keith number in base 10: 1, 4, 5, 9, 14...

Fourteen is an open meandric number.

Fourteen is a Companion Pell number.

In science

• The atomic number of silicon
• The upper limit of the pH scale.

In astronomy,

Messier object M14, a magnitude 9.5 globular cluster in the constellation Ophiuchus

The New General Catalogue object (http://www.ngcic.org/) NGC 14, a magnitude 12.5 irregular galaxy in the constellation Pegasus

The Saros number (http://sunearth.gsfc.nasa.gov/eclipse/SEsaros/SEsaros1-175.html) of the solar eclipse series which began on -2568 July 31 and ended on -1035 February 6. The duration of Saros series 14 was 1532.5 years, and it contained 86 solar eclipses.

The Saros number (http://sunearth.gsfc.nasa.gov/eclipse/LEsaros/LEsaros1-175.html) of the lunar eclipse series which began on -2230 June 1 and ended on -932 July 19. The duration of Saros series 14 was 1298.1 years, and it contained 73 lunar eclipses.

In other fields

Fourteen is:

• A number representing good luck in South American countries
• The number of days in a fortnight.
• In traditional British units of weight, the number of pounds in a stone.
• A number 'encoded' in a lot of the music of Johann Sebastian Bach. Bach may have considered this number a sort of signature, since given A = 1, B = 2, C = 3, etc., then B + A + C + H = 14 and J + S + B + A + C + H = 41.
• The number of points outlined by president Woodrow Wilson for reconstructing a new Europe following World War I, see Fourteen Points.
• Among neo-Nazis to signify the "14 words", "We must secure the existence of our people and a future for white children", attributed to David Lane.
• An unlucky number in China because it is homonymous with ???? which means "must die".
• The number of a Mexican street gang, the Norteños. It designates N, the fourteenth letter of the alphabet, which stands for "Northerner".
• The number of legs on a pillbug, as well as on Hallucigenia.
• Historical years: 14 A.D., 14 B.C., or 1914
• A common designation for the thirteenth floor in many buildings for superstitious reasons
• The G-14 is a union of fourtien football clubs.
• In rugby union the right wing wears the 14 shirt.
• The number of fonts included in a standard installation of Adobe Acrobat or Acrobat Reader (called "Base 14 fonts"). This set is the same as Base 13 fonts with the addition of Zapf Dingbats.
• The number of muqatta'at