161717531 has 12 divisors (see below), whose sum is σ = 178106832. Its totient is φ = 146537424.

The previous prime is 161717477. The next prime is 161717579. The reversal of 161717531 is 135717161.

It is a de Polignac number, because none of the positive numbers 2^k-161717531 is a prime.

It is a super-2 number, since 2×161717531² = 52305119665471922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161717581) 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, 1436 + ... + 18041.

It is an arithmetic number, because the mean of its divisors is an integer number (14842236).

Almost surely, 2^161717531 is an apocalyptic number.

161717531 is a deficient number, since it is larger than the sum of its proper divisors (16389301).

161717531 is a wasteful number, since it uses less digits than its factorization.

161717531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19538 (or 19519 counting only the distinct ones).

The product of its digits is 4410, while the sum is 32.

The square root of 161717531 is about 12716.8207898043. The cubic root of 161717531 is about 544.8191538678.

The spelling of 161717531 in words is "one hundred sixty-one million, seven hundred seventeen thousand, five hundred thirty-one".