138813631 has 4 divisors (see below), whose sum is σ = 151433064. Its totient is φ = 126194200.

The previous prime is 138813611. The next prime is 138813641. The reversal of 138813631 is 136318831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 136318831 = 11 ⋅12392621.

It is not a de Polignac number, because 138813631 - 2²⁵ = 105259199 is a prime.

It is a super-2 number, since 2×138813631² = 38538448302808322, 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 (138813611) 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, 6309700 + ... + 6309721.

It is an arithmetic number, because the mean of its divisors is an integer number (37858266).

Almost surely, 2^138813631 is an apocalyptic number.

138813631 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

138813631 is a deficient number, since it is larger than the sum of its proper divisors (12619433).

138813631 is a wasteful number, since it uses less digits than its factorization.

138813631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12619432.

The product of its digits is 10368, while the sum is 34.

The square root of 138813631 is about 11781.9196653177. The cubic root of 138813631 is about 517.7785299224.

The spelling of 138813631 in words is "one hundred thirty-eight million, eight hundred thirteen thousand, six hundred thirty-one".