138933906 has 16 divisors (see below), whose sum is σ = 279116544. Its totient is φ = 46103184.

The previous prime is 138933881. The next prime is 138933917. The reversal of 138933906 is 609339831.

138933906 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 50581 + ... + 53256.

It is an arithmetic number, because the mean of its divisors is an integer number (17444784).

Almost surely, 2^138933906 is an apocalyptic number.

138933906 is an abundant number, since it is smaller than the sum of its proper divisors (140182638).

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

138933906 is a wasteful number, since it uses less digits than its factorization.

138933906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104065.

The product of its (nonzero) digits is 104976, while the sum is 42.

The square root of 138933906 is about 11787.0227793112. The cubic root of 138933906 is about 517.9280297341.

The spelling of 138933906 in words is "one hundred thirty-eight million, nine hundred thirty-three thousand, nine hundred six".