138507631 has 2 divisors, whose sum is σ = 138507632. Its totient is φ = 138507630.

The previous prime is 138507617. The next prime is 138507641. The reversal of 138507631 is 136705831.

138507631 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 138507631 - 2⁵ = 138507599 is a prime.

It is a super-2 number, since 2×138507631² = 38368727690464322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138507641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69253815 + 69253816.

It is an arithmetic number, because the mean of its divisors is an integer number (69253816).

Almost surely, 2^138507631 is an apocalyptic number.

138507631 is a deficient number, since it is larger than the sum of its proper divisors (1).

138507631 is an equidigital number, since it uses as much as digits as its factorization.

138507631 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15120, while the sum is 34.

The square root of 138507631 is about 11768.9265015973. The cubic root of 138507631 is about 517.3977873076.

The spelling of 138507631 in words is "one hundred thirty-eight million, five hundred seven thousand, six hundred thirty-one".