138878868 has 24 divisors (see below), whose sum is σ = 330166368. Its totient is φ = 45419296.

The previous prime is 138878867. The next prime is 138878879. The reversal of 138878868 is 868878831.

It is a super-2 number, since 2×138878868² = 38574679953922848, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138878867) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 108546 + ... + 109817.

It is an arithmetic number, because the mean of its divisors is an integer number (13756932).

Almost surely, 2^138878868 is an apocalyptic number.

It is an amenable number.

138878868 is an abundant number, since it is smaller than the sum of its proper divisors (191287500).

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

138878868 is a wasteful number, since it uses less digits than its factorization.

138878868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218423 (or 218421 counting only the distinct ones).

The product of its digits is 4128768, while the sum is 57.

The square root of 138878868 is about 11784.6878617976. The cubic root of 138878868 is about 517.8596291334.

The spelling of 138878868 in words is "one hundred thirty-eight million, eight hundred seventy-eight thousand, eight hundred sixty-eight".