666651656 has 16 divisors (see below), whose sum is σ = 1363605840. Its totient is φ = 303023440.

The previous prime is 666651653. The next prime is 666651697. The reversal of 666651656 is 656156666.

It is a self number, because there is not a number n which added to its sum of digits gives 666651656.

It is not an unprimeable number, because it can be changed into a prime (666651653) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 3787706 + ... + 3787881.

It is an arithmetic number, because the mean of its divisors is an integer number (85225365).

Almost surely, 2^666651656 is an apocalyptic number.

It is an amenable number.

666651656 is an abundant number, since it is smaller than the sum of its proper divisors (696954184).

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

666651656 is a wasteful number, since it uses less digits than its factorization.

666651656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7575604 (or 7575600 counting only the distinct ones).

The product of its digits is 1166400, while the sum is 47.

The square root of 666651656 is about 25819.5982927698. The cubic root of 666651656 is about 873.5739081745.

The spelling of 666651656 in words is "six hundred sixty-six million, six hundred fifty-one thousand, six hundred fifty-six".