115565561 has 4 divisors (see below), whose sum is σ = 115621632. Its totient is φ = 115509492.

The previous prime is 115565539. The next prime is 115565579. The reversal of 115565561 is 165565511.

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.

It is a cyclic number.

It is not a de Polignac number, because 115565561 - 2¹⁸ = 115303417 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (115565761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24821 + ... + 29106.

It is an arithmetic number, because the mean of its divisors is an integer number (28905408).

Almost surely, 2^115565561 is an apocalyptic number.

It is an amenable number.

115565561 is a deficient number, since it is larger than the sum of its proper divisors (56071).

115565561 is an equidigital number, since it uses as much as digits as its factorization.

115565561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56070.

The product of its digits is 22500, while the sum is 35.

The square root of 115565561 is about 10750.1423711503. The cubic root of 115565561 is about 487.0902957908.

The spelling of 115565561 in words is "one hundred fifteen million, five hundred sixty-five thousand, five hundred sixty-one".