115909 has 4 divisors (see below), whose sum is σ = 119680. Its totient is φ = 112140.

The previous prime is 115903. The next prime is 115931. The reversal of 115909 is 909511.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 909511 = 19 ⋅47869.

It is a cyclic number.

It is not a de Polignac number, because 115909 - 2³ = 115901 is a prime.

It is a Duffinian number.

115909 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (115901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1839 + ... + 1900.

It is an arithmetic number, because the mean of its divisors is an integer number (29920).

2¹¹⁵⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

115909 is a deficient number, since it is larger than the sum of its proper divisors (3771).

115909 is an equidigital number, since it uses as much as digits as its factorization.

115909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3770.

The product of its (nonzero) digits is 405, while the sum is 25.

The square root of 115909 is about 340.4541085080. The cubic root of 115909 is about 48.7572332024.

It can be divided in two parts, 115 and 909, that added together give a 10-th power (1024 = 2¹⁰).

The spelling of 115909 in words is "one hundred fifteen thousand, nine hundred nine".