11666515655565 has 48 divisors (see below), whose sum is σ = 20312970163200. Its totient is φ = 6194143910016.

The previous prime is 11666515655527. The next prime is 11666515655567. The reversal of 11666515655565 is 56555651566611.

11666515655565 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 11666515655565 - 2¹¹ = 11666515653517 is a prime.

It is a super-2 number, since 2×11666515655565² (a number of 27 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11666515655567) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 120887151 + ... + 120983619.

It is an arithmetic number, because the mean of its divisors is an integer number (423186878400).

Almost surely, 2^{11666515655565} is an apocalyptic number.

11666515655565 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

11666515655565 is a deficient number, since it is larger than the sum of its proper divisors (8646454507635).

11666515655565 is a wasteful number, since it uses less digits than its factorization.

11666515655565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108546 (or 108543 counting only the distinct ones).

The product of its digits is 121500000, while the sum is 63.

The spelling of 11666515655565 in words is "eleven trillion, six hundred sixty-six billion, five hundred fifteen million, six hundred fifty-five thousand, five hundred sixty-five".