15

15 (fifteen) is a positive integer following 14 and preceding 16. Its ordinal form is written "15th" or "fifteenth".
== Properties ==
* 15 is an .
* 15 is the 5th .
* 15 is equal to 5!!, the double factorial of 5.
* 15 is the number for the French department of .
* In Czech language, 15 is called "mandel".
* 15 is the product of the first two Fermat primes.
* The integer part of ee is equal to 15.
== In googology ==
In Greek-based naming systems, 15 is associated with prefix "pentadeka-", and with prefix "quindeci-" in Latin systems.
DeepLineMadom calls the number zeroogolquadriplex, and is equal to 10[0]10[0]10[0]10[0]10[0]100 in DeepLineMadom's Array NotationDeepLineMadom's googology - Numbers I've coined (Retrieved 4 May 2022).
== As a banknote denomination ==
The third had banknotes with this number in the denomination.
== Puzzle ==
 is a puzzle with 15 squares.Britannica, Fifteen Puzzle
== Sources ==
Category:Numbers
Category:Banknote denominations
Category:Class 1
Category:Non-powers
Category:Numbers 0-99
Category:Numbers with 1 to 2 digits