138639900 has 144 divisors (see below), whose sum is σ = 463470336. Its totient is φ = 31342080.

The previous prime is 138639889. The next prime is 138639937. The reversal of 138639900 is 9936831.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 224392 + ... + 225008.

It is an arithmetic number, because the mean of its divisors is an integer number (3218544).

Almost surely, 2^138639900 is an apocalyptic number.

138639900 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138639900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (231735168).

138639900 is an abundant number, since it is smaller than the sum of its proper divisors (324830436).

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

138639900 is a wasteful number, since it uses less digits than its factorization.

138639900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 748 (or 741 counting only the distinct ones).

The product of its (nonzero) digits is 34992, while the sum is 39.

The square root of 138639900 is about 11774.5445771800. The cubic root of 138639900 is about 517.5624326646.

The spelling of 138639900 in words is "one hundred thirty-eight million, six hundred thirty-nine thousand, nine hundred".