666695666 has 48 divisors (see below), whose sum is σ = 1264558680. Its totient is φ = 261273600.

The previous prime is 666695597. The next prime is 666695683. The reversal of 666695666 is 666596666.

It can be written as a sum of positive squares in 4 ways, for example, as 541725625 + 124970041 = 23275^2 + 11179^2 .

It is a super-2 number, since 2×666695666² = 888966222126367112, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 136466 + ... + 141266.

Almost surely, 2^666695666 is an apocalyptic number.

666695666 is a deficient number, since it is larger than the sum of its proper divisors (597863014).

666695666 is a wasteful number, since it uses less digits than its factorization.

666695666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4939 (or 4932 counting only the distinct ones).

The product of its digits is 12597120, while the sum is 56.

The square root of 666695666 is about 25820.4505382846. The cubic root of 666695666 is about 873.5931311782.

The spelling of 666695666 in words is "six hundred sixty-six million, six hundred ninety-five thousand, six hundred sixty-six".