11561656656 has 40 divisors (see below), whose sum is σ = 32582852064. Its totient is φ = 3503532160.

The previous prime is 11561656643. The next prime is 11561656661. The reversal of 11561656656 is 65665616511.

It is a hoax number, since the sum of its digits (48) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10948011 + ... + 10949066.

Almost surely, 2^11561656656 is an apocalyptic number.

11561656656 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

11561656656 is an abundant number, since it is smaller than the sum of its proper divisors (21021195408).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

11561656656 is a wasteful number, since it uses less digits than its factorization.

11561656656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21897099 (or 21897093 counting only the distinct ones).

The product of its digits is 972000, while the sum is 48.

The spelling of 11561656656 in words is "eleven billion, five hundred sixty-one million, six hundred fifty-six thousand, six hundred fifty-six".