668556655866 has 96 divisors (see below), whose sum is σ = 1663740449280. Its totient is φ = 191890231200.

The previous prime is 668556655849. The next prime is 668556655873.

668556655866 is a `hidden beast` number, since 6 + 6 + 8 + 5 + 5 + 6 + 6 + 558 + 66 = 666.

668556655866 is nontrivially palindromic in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 668556655794 and 668556655803.

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 47 ways as a sum of consecutive naturals, for example, 21363811 + ... + 21395081.

It is an arithmetic number, because the mean of its divisors is an integer number (17330629680).

Almost surely, 2^668556655866 is an apocalyptic number.

668556655866 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 668556655866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (831870224640).

668556655866 is an abundant number, since it is smaller than the sum of its proper divisors (995183793414).

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

668556655866 is a wasteful number, since it uses less digits than its factorization.

668556655866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36992 (or 36989 counting only the distinct ones).

The product of its digits is 1866240000, while the sum is 72.

The spelling of 668556655866 in words is "six hundred sixty-eight billion, five hundred fifty-six million, six hundred fifty-five thousand, eight hundred sixty-six".