138393907 has 4 divisors (see below), whose sum is σ = 139687416. Its totient is φ = 137100400.

The previous prime is 138393883. The next prime is 138393961. The reversal of 138393907 is 709393831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 709393831 = 1453 ⋅488227.

It is a cyclic number.

It is not a de Polignac number, because 138393907 - 2²³ = 130005299 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138393977) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 646594 + ... + 646807.

It is an arithmetic number, because the mean of its divisors is an integer number (34921854).

Almost surely, 2^138393907 is an apocalyptic number.

138393907 is a deficient number, since it is larger than the sum of its proper divisors (1293509).

138393907 is a wasteful number, since it uses less digits than its factorization.

138393907 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1293508.

The product of its (nonzero) digits is 122472, while the sum is 43.

The square root of 138393907 is about 11764.0939727631. The cubic root of 138393907 is about 517.2561425070.

The spelling of 138393907 in words is "one hundred thirty-eight million, three hundred ninety-three thousand, nine hundred seven".