161387631 has 12 divisors (see below), whose sum is σ = 234513552. Its totient is φ = 106946496.

The previous prime is 161387627. The next prime is 161387641. The reversal of 161387631 is 136783161.

161387631 is a `hidden beast` number, since 1 + 6 + 13 + 8 + 7 + 631 = 666.

It is not a de Polignac number, because 161387631 - 2² = 161387627 is a prime.

It is a super-2 number, since 2×161387631² = 52091934879584322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161387621) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 52186 + ... + 55191.

It is an arithmetic number, because the mean of its divisors is an integer number (19542796).

Almost surely, 2^161387631 is an apocalyptic number.

161387631 is a deficient number, since it is larger than the sum of its proper divisors (73125921).

161387631 is a wasteful number, since it uses less digits than its factorization.

161387631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107550 (or 107547 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 161387631 is about 12703.8431586666. The cubic root of 161387631 is about 544.4484288647.

The spelling of 161387631 in words is "one hundred sixty-one million, three hundred eighty-seven thousand, six hundred thirty-one".