665725806 has 24 divisors (see below), whose sum is σ = 1488936384. Its totient is φ = 214750080.

The previous prime is 665725799. The next prime is 665725849. The reversal of 665725806 is 608527566.

665725806 is a `hidden beast` number, since 6 + 65 + 7 + 2 + 580 + 6 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 595971 + ... + 597086.

It is an arithmetic number, because the mean of its divisors is an integer number (62039016).

Almost surely, 2^665725806 is an apocalyptic number.

665725806 is an abundant number, since it is smaller than the sum of its proper divisors (823210578).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

665725806 is a wasteful number, since it uses less digits than its factorization.

665725806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1193096 (or 1193093 counting only the distinct ones).

The product of its (nonzero) digits is 604800, while the sum is 45.

The square root of 665725806 is about 25801.6628533899. The cubic root of 665725806 is about 873.1693125079.

The spelling of 665725806 in words is "six hundred sixty-five million, seven hundred twenty-five thousand, eight hundred six".