668879978866 has 64 divisors (see below), whose sum is σ = 1181796739200. Its totient is φ = 280638259200.

The previous prime is 668879978857. The next prime is 668879978869.

668879978866 is nontrivially palindromic in base 10.

668879978866 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×668879978866² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (668879978869) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13153746 + ... + 13204498.

It is an arithmetic number, because the mean of its divisors is an integer number (18465574050).

Almost surely, 2^668879978866 is an apocalyptic number.

668879978866 is a deficient number, since it is larger than the sum of its proper divisors (512916760334).

668879978866 is a wasteful number, since it uses less digits than its factorization.

668879978866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51595.

The product of its digits is 21069103104, while the sum is 88.

The spelling of 668879978866 in words is "six hundred sixty-eight billion, eight hundred seventy-nine million, nine hundred seventy-eight thousand, eight hundred sixty-six".