666491908 has 6 divisors (see below), whose sum is σ = 1166360846. Its totient is φ = 333245952.

The previous prime is 666491893. The next prime is 666491911. The reversal of 666491908 is 809194666.

666491908 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 549808704 + 116683204 = 23448^2 + 10802^2 .

It is a super-2 number, since 2×666491908² = 888422926858960928, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83311485 + ... + 83311492.

Almost surely, 2^666491908 is an apocalyptic number.

It is an amenable number.

666491908 is a deficient number, since it is larger than the sum of its proper divisors (499868938).

666491908 is a wasteful number, since it uses less digits than its factorization.

666491908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166622981 (or 166622979 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 49.

The square root of 666491908 is about 25816.5045658780. The cubic root of 666491908 is about 873.5041251868.

The spelling of 666491908 in words is "six hundred sixty-six million, four hundred ninety-one thousand, nine hundred eight".