138388638 has 16 divisors (see below), whose sum is σ = 286321680. Its totient is φ = 44538816.

The previous prime is 138388597. The next prime is 138388651. The reversal of 138388638 is 836883831.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 397495 + ... + 397842.

It is an arithmetic number, because the mean of its divisors is an integer number (17895105).

Almost surely, 2^138388638 is an apocalyptic number.

138388638 is an abundant number, since it is smaller than the sum of its proper divisors (147933042).

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

138388638 is a wasteful number, since it uses less digits than its factorization.

138388638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 795371.

The product of its digits is 663552, while the sum is 48.

The square root of 138388638 is about 11763.8700264836. The cubic root of 138388638 is about 517.2495780147.

The spelling of 138388638 in words is "one hundred thirty-eight million, three hundred eighty-eight thousand, six hundred thirty-eight".