138738631 has 4 divisors (see below), whose sum is σ = 140085712. Its totient is φ = 137391552.

The previous prime is 138738569. The next prime is 138738659. The reversal of 138738631 is 136837831.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 138738631 - 2⁷ = 138738503 is a prime.

It is a super-2 number, since 2×138738631² = 38496815463508322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138738731) 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, 673386 + ... + 673591.

It is an arithmetic number, because the mean of its divisors is an integer number (35021428).

Almost surely, 2^138738631 is an apocalyptic number.

138738631 is a deficient number, since it is larger than the sum of its proper divisors (1347081).

138738631 is a wasteful number, since it uses less digits than its factorization.

138738631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1347080.

The product of its digits is 72576, while the sum is 40.

The square root of 138738631 is about 11778.7363923300. The cubic root of 138738631 is about 517.6852624593.

The spelling of 138738631 in words is "one hundred thirty-eight million, seven hundred thirty-eight thousand, six hundred thirty-one".