115665561 has 12 divisors (see below), whose sum is σ = 182261040. Its totient is φ = 70100280.

The previous prime is 115665541. The next prime is 115665581. The reversal of 115665561 is 165566511.

It is an interprime number because it is at equal distance from previous prime (115665541) and next prime (115665581).

It is not a de Polignac number, because 115665561 - 2⁶ = 115665497 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (115665541) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 584071 + ... + 584268.

It is an arithmetic number, because the mean of its divisors is an integer number (15188420).

Almost surely, 2^115665561 is an apocalyptic number.

115665561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

115665561 is a deficient number, since it is larger than the sum of its proper divisors (66595479).

115665561 is a wasteful number, since it uses less digits than its factorization.

115665561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1168356 (or 1168353 counting only the distinct ones).

The product of its digits is 27000, while the sum is 36.

The square root of 115665561 is about 10754.7924666169. The cubic root of 115665561 is about 487.2307499378.

The spelling of 115665561 in words is "one hundred fifteen million, six hundred sixty-five thousand, five hundred sixty-one".