666626660 has 24 divisors (see below), whose sum is σ = 1599904320. Its totient is φ = 228557664.

The previous prime is 666626659. The next prime is 666626699. The reversal of 666626660 is 66626666.

It is a super-2 number, since 2×666626660² = 888782207645511200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2380670 + ... + 2380949.

It is an arithmetic number, because the mean of its divisors is an integer number (66662680).

Almost surely, 2^666626660 is an apocalyptic number.

It is an amenable number.

666626660 is an abundant number, since it is smaller than the sum of its proper divisors (933277660).

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

666626660 is a wasteful number, since it uses less digits than its factorization.

666626660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4761635 (or 4761633 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 44.

The square root of 666626660 is about 25819.1142373243. The cubic root of 666626660 is about 873.5629898655.

The spelling of 666626660 in words is "six hundred sixty-six million, six hundred twenty-six thousand, six hundred sixty".