138931207 has 2 divisors, whose sum is σ = 138931208. Its totient is φ = 138931206.

The previous prime is 138931193. The next prime is 138931223. The reversal of 138931207 is 702139831.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 138931207 - 2²⁷ = 4713479 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138931277) 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 as a sum of consecutive naturals, namely, 69465603 + 69465604.

It is an arithmetic number, because the mean of its divisors is an integer number (69465604).

Almost surely, 2^138931207 is an apocalyptic number.

138931207 is a deficient number, since it is larger than the sum of its proper divisors (1).

138931207 is an equidigital number, since it uses as much as digits as its factorization.

138931207 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 138931207 is about 11786.9082884359. The cubic root of 138931207 is about 517.9246758688.

The spelling of 138931207 in words is "one hundred thirty-eight million, nine hundred thirty-one thousand, two hundred seven".