656811666 has 40 divisors (see below), whose sum is σ = 1681996800. Its totient is φ = 187660152.

The previous prime is 656811647. The next prime is 656811707. The reversal of 656811666 is 666118656.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 288466 + ... + 290733.

It is an arithmetic number, because the mean of its divisors is an integer number (42049920).

Almost surely, 2^656811666 is an apocalyptic number.

656811666 is an abundant number, since it is smaller than the sum of its proper divisors (1025185134).

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

656811666 is a wasteful number, since it uses less digits than its factorization.

656811666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 579220 (or 579211 counting only the distinct ones).

The product of its digits is 311040, while the sum is 45.

The square root of 656811666 is about 25628.3371680646. The cubic root of 656811666 is about 869.2545100158.

The spelling of 656811666 in words is "six hundred fifty-six million, eight hundred eleven thousand, six hundred sixty-six".