668910685 has 4 divisors (see below), whose sum is σ = 802692828. Its totient is φ = 535128544.

The previous prime is 668910601. The next prime is 668910727. The reversal of 668910685 is 586019866.

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

It can be written as a sum of positive squares in 2 ways, for example, as 496487524 + 172423161 = 22282^2 + 13131^2 .

It is a cyclic number.

It is not a de Polignac number, because 668910685 - 2²⁹ = 132039773 is a prime.

It is a Duffinian number.

It is a congruent number.

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, 66891064 + ... + 66891073.

It is an arithmetic number, because the mean of its divisors is an integer number (200673207).

Almost surely, 2^668910685 is an apocalyptic number.

It is an amenable number.

668910685 is a deficient number, since it is larger than the sum of its proper divisors (133782143).

668910685 is a wasteful number, since it uses less digits than its factorization.

668910685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133782142.

The product of its (nonzero) digits is 622080, while the sum is 49.

The square root of 668910685 is about 25863.3076964258. The cubic root of 668910685 is about 874.5595323231.

The spelling of 668910685 in words is "six hundred sixty-eight million, nine hundred ten thousand, six hundred eighty-five".