15 (number)

This article is about the number fifteen. For the year, see 15.

15 (fifteen) is a number. It is between fourteen and sixteen, and is an odd number. It is divisible by 1, 3, 5, and 15.

← 14 15 16 →
← 10 11 12 13 14 15 16 17 18 19 → ← 0 10 20 30 40 50 60 70 80 90 →
Cardinal	fifteen, fim
Ordinal	15th (fifteenth, fimth)
Factorization	3 · 5
Divisors	1, 3, 5, 15
Roman numeral	XV
Binary	11112
Ternary	1203
Quaternary	334
Quinary	305
Senary	236
Octal	178
Duodecimal	1312
Hexadecimal	F16
Vigesimal	F20
Base 36	F36
Hebrew	ט"ו (Tet Vav)

In Roman numerals, 15 is written as XV.

15 (number) Media

• 

  The unique magic square of order 3.

• The 15 perfect matchings of K6

• 15 as the difference of two positive squares (in orange).

• 

  Seashells from the mollusk Donax variabilis have 15 coloring pattern phenotypes.