115661865 has 32 divisors (see below), whose sum is σ = 203461632. Its totient is φ = 55640000.

The previous prime is 115661851. The next prime is 115661869. The reversal of 115661865 is 568166511.

It is not a de Polignac number, because 115661865 - 2⁶ = 115661801 is a prime.

It is not an unprimeable number, because it can be changed into a prime (115661869) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18940 + ... + 24290.

It is an arithmetic number, because the mean of its divisors is an integer number (6358176).

Almost surely, 2^115661865 is an apocalyptic number.

115661865 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

115661865 is a deficient number, since it is larger than the sum of its proper divisors (87799767).

115661865 is a wasteful number, since it uses less digits than its factorization.

115661865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5501.

The product of its digits is 43200, while the sum is 39.

The square root of 115661865 is about 10754.6206348713. The cubic root of 115661865 is about 487.2255601936.

It can be divided in two parts, 11566 and 1865, that added together give a palindrome (13431).

The spelling of 115661865 in words is "one hundred fifteen million, six hundred sixty-one thousand, eight hundred sixty-five".