668644985 has 16 divisors (see below), whose sum is σ = 822856320. Its totient is φ = 521431680.

The previous prime is 668644943. The next prime is 668645009. The reversal of 668644985 is 589446866.

668644985 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 668644985 - 2¹⁰ = 668643961 is a prime.

It is a super-2 number, since 2×668644985² = 894172231931300450, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 668644985.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21014 + ... + 42176.

It is an arithmetic number, because the mean of its divisors is an integer number (51428520).

Almost surely, 2^668644985 is an apocalyptic number.

It is an amenable number.

668644985 is a deficient number, since it is larger than the sum of its proper divisors (154211335).

668644985 is a wasteful number, since it uses less digits than its factorization.

668644985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21328.

The product of its digits is 9953280, while the sum is 56.

The square root of 668644985 is about 25858.1705656065. The cubic root of 668644985 is about 874.4437215247.

The spelling of 668644985 in words is "six hundred sixty-eight million, six hundred forty-four thousand, nine hundred eighty-five".