138878920 has 64 divisors (see below), whose sum is σ = 322056000. Its totient is φ = 53875968.

The previous prime is 138878897. The next prime is 138878959. The reversal of 138878920 is 29878831.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 195526 + ... + 196234.

It is an arithmetic number, because the mean of its divisors is an integer number (5032125).

Almost surely, 2^138878920 is an apocalyptic number.

138878920 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 138878920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (161028000).

138878920 is an abundant number, since it is smaller than the sum of its proper divisors (183177080).

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

138878920 is a wasteful number, since it uses less digits than its factorization.

138878920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 862 (or 858 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 46.

The square root of 138878920 is about 11784.6900680502. The cubic root of 138878920 is about 517.8596937669.

It can be divided in two parts, 1388 and 78920, that added together give a palindrome (80308).

The spelling of 138878920 in words is "one hundred thirty-eight million, eight hundred seventy-eight thousand, nine hundred twenty".