168138631 has 16 divisors (see below), whose sum is σ = 175890528. Its totient is φ = 160617600.

The previous prime is 168138629. The next prime is 168138667. The reversal of 168138631 is 136831861.

It is a cyclic number.

It is not a de Polignac number, because 168138631 - 2¹ = 168138629 is a prime.

It is a super-2 number, since 2×168138631² = 56541198469108322, 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 (168138601) 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 in 15 ways as a sum of consecutive naturals, for example, 423325 + ... + 423721.

It is an arithmetic number, because the mean of its divisors is an integer number (10993158).

Almost surely, 2^168138631 is an apocalyptic number.

168138631 is a deficient number, since it is larger than the sum of its proper divisors (7751897).

168138631 is a wasteful number, since it uses less digits than its factorization.

168138631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 642.

The product of its digits is 20736, while the sum is 37.

The square root of 168138631 is about 12966.8281009659. The cubic root of 168138631 is about 551.9365683168.

The spelling of 168138631 in words is "one hundred sixty-eight million, one hundred thirty-eight thousand, six hundred thirty-one".