668625866 has 4 divisors (see below), whose sum is σ = 1002938802. Its totient is φ = 334312932.

The previous prime is 668625863. The next prime is 668625931. The reversal of 668625866 is 668526866.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 612810025 + 55815841 = 24755^2 + 7471^2 .

It is not an unprimeable number, because it can be changed into a prime (668625863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 167156465 + ... + 167156468.

Almost surely, 2^668625866 is an apocalyptic number.

668625866 is a deficient number, since it is larger than the sum of its proper divisors (334312936).

668625866 is a wasteful number, since it uses less digits than its factorization.

668625866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 334312935.

The product of its digits is 4976640, while the sum is 53.

The square root of 668625866 is about 25857.8008732375. The cubic root of 668625866 is about 874.4353869330.

The spelling of 668625866 in words is "six hundred sixty-eight million, six hundred twenty-five thousand, eight hundred sixty-six".