665856585 has 16 divisors (see below), whose sum is σ = 1183745280. Its totient is φ = 355123440.

The previous prime is 665856571. The next prime is 665856589. The reversal of 665856585 is 585658566.

665856585 is a `hidden beast` number, since 6 + 6 + 5 + 8 + 56 + 585 = 666.

It is a de Polignac number, because none of the positive numbers 2^k-665856585 is a prime.

It is not an unprimeable number, because it can be changed into a prime (665856589) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2466001 + ... + 2466270.

It is an arithmetic number, because the mean of its divisors is an integer number (73984080).

Almost surely, 2^665856585 is an apocalyptic number.

It is an amenable number.

665856585 is a deficient number, since it is larger than the sum of its proper divisors (517888695).

665856585 is a wasteful number, since it uses less digits than its factorization.

665856585 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4932285 (or 4932279 counting only the distinct ones).

The product of its digits is 8640000, while the sum is 54.

The square root of 665856585 is about 25804.1970423418. The cubic root of 665856585 is about 873.2264855621.

The spelling of 665856585 in words is "six hundred sixty-five million, eight hundred fifty-six thousand, five hundred eighty-five".