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

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Cardinal | one hundred fifteen | |||

Ordinal | 115th (one hundred fifteenth) | |||

Factorization | 5 × 23 | |||

Divisors | 1, 5, 23, 115 | |||

Greek numeral | ΡΙΕ´ | |||

Roman numeral | CXV | |||

Binary | 1110011_{2} | |||

Ternary | 11021_{3} | |||

Octal | 163_{8} | |||

Duodecimal | 97_{12} | |||

Hexadecimal | 73_{16} |

115 has a square sum of divisors:^{[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]}
115 is the sum of the first five heptagonal numbers.

**^**Sloane, N. J. A. (ed.). "Sequence A006532 (Numbers n such that sum of divisors of n is a square)".*The On-Line Encyclopedia of Integer Sequences*. OEIS Foundation.**^**Sloane, N. J. A. (ed.). "Sequence A000081 (Number of rooted trees with n nodes (or connected functions with a fixed point))".*The On-Line Encyclopedia of Integer Sequences*. OEIS Foundation.**^**Sloane, N. J. A. (ed.). "Sequence A000903 (Number of inequivalent ways of placing n nonattacking rooks on n X n board)".*The On-Line Encyclopedia of Integer Sequences*. OEIS Foundation.**^**Sloane, N. J. A. (ed.). "Sequence A002369 (Number of ways of folding a strip of n rectangular stamps)".*The On-Line Encyclopedia of Integer Sequences*. OEIS Foundation.**^**Sloane, N. J. A. (ed.). "Sequence A002413 (Heptagonal (or 7-gonal) pyramidal numbers: n*(n+1)*(5*n-2)/6)".*The On-Line Encyclopedia of Integer Sequences*. OEIS Foundation.**^**Sloane, N. J. A. (ed.). "Sequence A002234 (Numbers n such that the Woodall number n*2^n - 1 is prime)".*The On-Line Encyclopedia of Integer Sequences*. OEIS Foundation.