666556616 has 16 divisors (see below), whose sum is σ = 1363411440. Its totient is φ = 302980240.

The previous prime is 666556543. The next prime is 666556643. The reversal of 666556616 is 616655666.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3787166 + ... + 3787341.

It is an arithmetic number, because the mean of its divisors is an integer number (85213215).

Almost surely, 2^666556616 is an apocalyptic number.

It is an amenable number.

666556616 is an abundant number, since it is smaller than the sum of its proper divisors (696854824).

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

666556616 is a wasteful number, since it uses less digits than its factorization.

666556616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7574524 (or 7574520 counting only the distinct ones).

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

The square root of 666556616 is about 25817.7577647634. The cubic root of 666556616 is about 873.5323930348.

The spelling of 666556616 in words is "six hundred sixty-six million, five hundred fifty-six thousand, six hundred sixteen".