# 115 (number)

Short description: Natural 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] 115 is the sum of the first five heptagonal numbers.