639568388 has 12 divisors (see below), whose sum is σ = 1126374732. Its totient is φ = 317747040.

The previous prime is 639568357. The next prime is 639568393. The reversal of 639568388 is 883865936.

It can be written as a sum of positive squares in 2 ways, for example, as 365268544 + 274299844 = 19112^2 + 16562^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 508583 + ... + 509838.

It is an arithmetic number, because the mean of its divisors is an integer number (93864561).

Almost surely, 2^639568388 is an apocalyptic number.

It is an amenable number.

639568388 is a deficient number, since it is larger than the sum of its proper divisors (486806344).

639568388 is a wasteful number, since it uses less digits than its factorization.

639568388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1018582 (or 1018580 counting only the distinct ones).

The product of its digits is 7464960, while the sum is 56.

The square root of 639568388 is about 25289.6893614769. The cubic root of 639568388 is about 861.5801074755.

The spelling of 639568388 in words is "six hundred thirty-nine million, five hundred sixty-eight thousand, three hundred eighty-eight".