668909866 has 8 divisors (see below), whose sum is σ = 1013709060. Its totient is φ = 331006848.

The previous prime is 668909833. The next prime is 668909881.

668909866 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 2 ways, for example, as 661775625 + 7134241 = 25725^2 + 2671^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 668909866.

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, 1723801 + ... + 1724188.

Almost surely, 2^668909866 is an apocalyptic number.

668909866 is a deficient number, since it is larger than the sum of its proper divisors (344799194).

668909866 is a wasteful number, since it uses less digits than its factorization.

668909866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3448088.

The product of its (nonzero) digits is 6718464, while the sum is 58.

The square root of 668909866 is about 25863.2918631794. The cubic root of 668909866 is about 874.5591753922.

The spelling of 668909866 in words is "six hundred sixty-eight million, nine hundred nine thousand, eight hundred sixty-six".