639863986136 has 32 divisors (see below), whose sum is σ = 1314122292000. Its totient is φ = 290729273856.

The previous prime is 639863986133. The next prime is 639863986141. The reversal of 639863986136 is 631689368936.

It is a Harshad number since it is a multiple of its sum of digits (68).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639863986133) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 81114716 + ... + 81122603.

It is an arithmetic number, because the mean of its divisors is an integer number (41066321625).

Almost surely, 2^639863986136 is an apocalyptic number.

It is an amenable number.

639863986136 is an abundant number, since it is smaller than the sum of its proper divisors (674258305864).

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

639863986136 is a wasteful number, since it uses less digits than its factorization.

639863986136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162237371 (or 162237367 counting only the distinct ones).

The product of its digits is 181398528, while the sum is 68.

The spelling of 639863986136 in words is "six hundred thirty-nine billion, eight hundred sixty-three million, nine hundred eighty-six thousand, one hundred thirty-six".