161516231 has 6 divisors (see below), whose sum is σ = 166895496. Its totient is φ = 156305100.

The previous prime is 161516203. The next prime is 161516233. The reversal of 161516231 is 132615161.

It is not a de Polignac number, because 161516231 - 2¹⁸ = 161254087 is a prime.

It is a super-2 number, since 2×161516231² = 52174985752890722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161516231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161516233) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 83075 + ... + 84996.

It is an arithmetic number, because the mean of its divisors is an integer number (27815916).

Almost surely, 2^161516231 is an apocalyptic number.

161516231 is a deficient number, since it is larger than the sum of its proper divisors (5379265).

161516231 is an equidigital number, since it uses as much as digits as its factorization.

161516231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168133 (or 168102 counting only the distinct ones).

The product of its digits is 1080, while the sum is 26.

The square root of 161516231 is about 12708.9036112483. The cubic root of 161516231 is about 544.5930030979.

The spelling of 161516231 in words is "one hundred sixty-one million, five hundred sixteen thousand, two hundred thirty-one".