138658631 has 4 divisors (see below), whose sum is σ = 138869064. Its totient is φ = 138448200.

The previous prime is 138658621. The next prime is 138658633. The reversal of 138658631 is 136856831.

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 138658631 - 2¹⁴ = 138642247 is a prime.

It is a super-2 number, since 2×138658631² = 38452431901588322, 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 (138658633) 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, 104225 + ... + 105546.

It is an arithmetic number, because the mean of its divisors is an integer number (34717266).

Almost surely, 2^138658631 is an apocalyptic number.

138658631 is a deficient number, since it is larger than the sum of its proper divisors (210433).

138658631 is an equidigital number, since it uses as much as digits as its factorization.

138658631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210432.

The product of its digits is 103680, while the sum is 41.

The square root of 138658631 is about 11775.3399526298. The cubic root of 138658631 is about 517.5857401092.

The spelling of 138658631 in words is "one hundred thirty-eight million, six hundred fifty-eight thousand, six hundred thirty-one".