161531316 has 36 divisors (see below), whose sum is σ = 409427200. Its totient is φ = 53697168.

The previous prime is 161531303. The next prime is 161531317. The reversal of 161531316 is 613135161.

161531316 is a `hidden beast` number, since 1 + 615 + 31 + 3 + 16 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a self number, because there is not a number n which added to its sum of digits gives 161531316.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161531317) 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, 7725 + ... + 19563.

Almost surely, 2^161531316 is an apocalyptic number.

It is an amenable number.

161531316 is an abundant number, since it is smaller than the sum of its proper divisors (247895884).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161531316 is a wasteful number, since it uses less digits than its factorization.

161531316 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12228 (or 12223 counting only the distinct ones).

The product of its digits is 1620, while the sum is 27.

The square root of 161531316 is about 12709.4970789564. The cubic root of 161531316 is about 544.6099568733.

Adding to 161531316 its reverse (613135161), we get a palindrome (774666477).

The spelling of 161531316 in words is "one hundred sixty-one million, five hundred thirty-one thousand, three hundred sixteen".