138836638 has 4 divisors (see below), whose sum is σ = 208254960. Its totient is φ = 69418318.

The previous prime is 138836623. The next prime is 138836639. The reversal of 138836638 is 836638831.

138836638 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×138836638² = 38551224102286088, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138836639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34709158 + ... + 34709161.

It is an arithmetic number, because the mean of its divisors is an integer number (52063740).

Almost surely, 2^138836638 is an apocalyptic number.

138836638 is a deficient number, since it is larger than the sum of its proper divisors (69418322).

138836638 is an equidigital number, since it uses as much as digits as its factorization.

138836638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69418321.

The product of its digits is 497664, while the sum is 46.

The square root of 138836638 is about 11782.8959937700. The cubic root of 138836638 is about 517.8071339159.

The spelling of 138836638 in words is "one hundred thirty-eight million, eight hundred thirty-six thousand, six hundred thirty-eight".