11566515555 has 64 divisors (see below), whose sum is σ = 24258355200. Its totient is φ = 5116970880.

The previous prime is 11566515533. The next prime is 11566515557. The reversal of 11566515555 is 55551566511.

It is not a de Polignac number, because 11566515555 - 2⁵ = 11566515523 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 11566515555.

It is not an unprimeable number, because it can be changed into a prime (11566515557) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 168120 + ... + 226709.

It is an arithmetic number, because the mean of its divisors is an integer number (379036800).

Almost surely, 2^11566515555 is an apocalyptic number.

11566515555 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

11566515555 is an abundant number, since it is smaller than the sum of its proper divisors (12691839645).

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

11566515555 is a wasteful number, since it uses less digits than its factorization.

11566515555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 394881 (or 394875 counting only the distinct ones).

The product of its digits is 562500, while the sum is 45.

The spelling of 11566515555 in words is "eleven billion, five hundred sixty-six million, five hundred fifteen thousand, five hundred fifty-five".