639873236564 has 12 divisors (see below), whose sum is σ = 1120674712500. Its totient is φ = 319680461568.

The previous prime is 639873236543. The next prime is 639873236579. The reversal of 639873236564 is 465632378936.

It can be written as a sum of positive squares in 2 ways, for example, as 295881602500 + 343991634064 = 543950^2 + 586508^2 .

It is a junction number, because it is equal to n+sod(n) for n = 639873236497 and 639873236506.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64033559 + ... + 64043550.

It is an arithmetic number, because the mean of its divisors is an integer number (93389559375).

Almost surely, 2^639873236564 is an apocalyptic number.

It is an amenable number.

639873236564 is a deficient number, since it is larger than the sum of its proper divisors (480801475936).

639873236564 is a wasteful number, since it uses less digits than its factorization.

639873236564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128078362 (or 128078360 counting only the distinct ones).

The product of its digits is 117573120, while the sum is 62.

The spelling of 639873236564 in words is "six hundred thirty-nine billion, eight hundred seventy-three million, two hundred thirty-six thousand, five hundred sixty-four".