115815591 has 6 divisors (see below), whose sum is σ = 167289200. Its totient is φ = 77210388.

The previous prime is 115815571. The next prime is 115815593. The reversal of 115815591 is 195518511.

115815591 is a `hidden beast` number, since 1 + 1 + 58 + 15 + 591 = 666.

It is not a de Polignac number, because 115815591 - 2⁵ = 115815559 is a prime.

It is a super-2 number, since 2×115815591² = 26826502237358562, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (115815593) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6434191 + ... + 6434208.

Almost surely, 2^115815591 is an apocalyptic number.

115815591 is a deficient number, since it is larger than the sum of its proper divisors (51473609).

115815591 is a wasteful number, since it uses less digits than its factorization.

115815591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12868405 (or 12868402 counting only the distinct ones).

The product of its digits is 9000, while the sum is 36.

The square root of 115815591 is about 10761.7652362426. The cubic root of 115815591 is about 487.4413215370.

The spelling of 115815591 in words is "one hundred fifteen million, eight hundred fifteen thousand, five hundred ninety-one".