# 115 (number)

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 ← 114 115 116 →
Cardinal one hundred fifteen
Ordinal 115th
(one hundred fifteenth)
Factorization 5 × 23
Divisors 1, 5, 23, 115
Greek numeral ΡΙΕ´
Roman numeral CXV
Binary 11100112
Ternary 110213
Quaternary 13034
Quinary 4305
Senary 3116
Octal 1638
Duodecimal 9712
Hexadecimal 7316
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:[1]

${\displaystyle \sigma (115)=1+5+23+115=144=12^{2}.}$

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,

${\displaystyle 115\cdot 2^{115}-1=4\;776\;913\;109\;852\;041\;418\;248\;056\;622\;882\;488\;319,}$

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]