# 115 (number)

 ← 114 115 116 →
Cardinal one hundred fifteen
Ordinal 115th
(one hundred and fifteenth)
Factorization 5 × 23
Divisors 1, 5, 23, 115
Roman numeral CXV
Binary 11100112
Ternary 110213
Quaternary 13034
Quinary 4305
Senary 3116
Octal 1638
Duodecimal 9712
Vigesimal 5F20
Base 36 3736

115 (one hundred [and] fifteen) is the natural number following 114 and preceding 116.

## In mathematics

115 has a square sum of divisors:

It is unknown whether the set of numbers with this property is infinite, but this would follow from the truth of the Bunyakovsky conjecture on polynomials with infinitely many prime values.[1]

There are 115 different rooted trees with exactly eight nodes,[2] 115 inequivalent ways of placing six rooks on a 6 × 6 chess board in such a way that no two of the rooks attack each other,[3] and 115 solutions to the stamp folding problem for a strip of seven stamps.[4]

115 is also a heptagonal pyramidal number.[5] The 115th Woodall number,

is a prime number.[6]

## In other fields

115 is also the fire service emergency number in Mauritius[7] and Italy,[8] and the ambulance emergency number in Vietnam.[9]