138923988 has 48 divisors (see below), whose sum is σ = 373887360. Its totient is φ = 39325824.

The previous prime is 138923977. The next prime is 138923999. The reversal of 138923988 is 889329831.

It is an interprime number because it is at equal distance from previous prime (138923977) and next prime (138923999).

It is a self number, because there is not a number n which added to its sum of digits gives 138923988.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1570 + ... + 16742.

It is an arithmetic number, because the mean of its divisors is an integer number (7789320).

Almost surely, 2^138923988 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138923988, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (186943680).

138923988 is an abundant number, since it is smaller than the sum of its proper divisors (234963372).

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

138923988 is a wasteful number, since it uses less digits than its factorization.

138923988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15296 (or 15294 counting only the distinct ones).

The product of its digits is 746496, while the sum is 51.

The square root of 138923988 is about 11786.6020548757. The cubic root of 138923988 is about 517.9157050909.

The spelling of 138923988 in words is "one hundred thirty-eight million, nine hundred twenty-three thousand, nine hundred eighty-eight".