# 115 (number)

 ← 114 115 116 →
Cardinalone hundred fifteen
Ordinal115th
(one hundred fifteenth)
Factorization5 × 23
Divisors1, 5, 23, 115
Greek numeralΡΙΕ´
Roman numeralCXV
Binary11100112
Ternary110213
Quaternary13034
Quinary4305
Senary3116
Octal1638
Duodecimal9712
Vigesimal5F20
Base 363736

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]