138878999 has 16 divisors (see below), whose sum is σ = 172838400. Its totient is φ = 108882144.

The previous prime is 138878983. The next prime is 138879017. The reversal of 138878999 is 999878831.

It is not a de Polignac number, because 138878999 - 2⁴ = 138878983 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138878959) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14147 + ... + 21860.

It is an arithmetic number, because the mean of its divisors is an integer number (10802400).

Almost surely, 2^138878999 is an apocalyptic number.

138878999 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

138878999 is a deficient number, since it is larger than the sum of its proper divisors (33959401).

138878999 is a wasteful number, since it uses less digits than its factorization.

138878999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36062.

The product of its digits is 7838208, while the sum is 62.

The square root of 138878999 is about 11784.6934198561. The cubic root of 138878999 is about 517.8597919602.

The spelling of 138878999 in words is "one hundred thirty-eight million, eight hundred seventy-eight thousand, nine hundred ninety-nine".