666558565855666 has 48 divisors (see below), whose sum is σ = 1136911441921920. Its totient is φ = 292528463119200.

The previous prime is 666558565855657. The next prime is 666558565855711.

666558565855666 is nontrivially palindromic in base 10.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 418818985 + ... + 420407491.

It is an arithmetic number, because the mean of its divisors is an integer number (23685655040040).

Almost surely, 2^{666558565855666} is an apocalyptic number.

666558565855666 is a deficient number, since it is larger than the sum of its proper divisors (470352876066254).

666558565855666 is a wasteful number, since it uses less digits than its factorization.

666558565855666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1648351 (or 1648340 counting only the distinct ones).

The product of its digits is 279936000000, while the sum is 88.

The spelling of 666558565855666 in words is "six hundred sixty-six trillion, five hundred fifty-eight billion, five hundred sixty-five million, eight hundred fifty-five thousand, six hundred sixty-six".