138731536638 has 24 divisors (see below), whose sum is σ = 300605865768. Its totient is φ = 46240634832.

The previous prime is 138731536627. The next prime is 138731536673. The reversal of 138731536638 is 836635137831.

138731536638 is a `hidden beast` number, since 1 + 3 + 8 + 73 + 1 + 536 + 6 + 38 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6481 + ... + 526787.

It is an arithmetic number, because the mean of its divisors is an integer number (12525244407).

Almost surely, 2^138731536638 is an apocalyptic number.

138731536638 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

138731536638 is an abundant number, since it is smaller than the sum of its proper divisors (161874329130).

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

138731536638 is a wasteful number, since it uses less digits than its factorization.

138731536638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 535128 (or 535125 counting only the distinct ones).

The product of its digits is 6531840, while the sum is 54.

The spelling of 138731536638 in words is "one hundred thirty-eight billion, seven hundred thirty-one million, five hundred thirty-six thousand, six hundred thirty-eight".