161857031 has 16 divisors (see below), whose sum is σ = 190080000. Its totient is φ = 134936928.

The previous prime is 161856979. The next prime is 161857103. The reversal of 161857031 is 130758161.

It is not a de Polignac number, because 161857031 - 2¹⁰ = 161856007 is a prime.

It is a super-2 number, since 2×161857031² = 52395396968269922, 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 (161857931) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 79970 + ... + 81968.

It is an arithmetic number, because the mean of its divisors is an integer number (11880000).

Almost surely, 2^161857031 is an apocalyptic number.

161857031 is a deficient number, since it is larger than the sum of its proper divisors (28222969).

161857031 is a wasteful number, since it uses less digits than its factorization.

161857031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2318.

The product of its (nonzero) digits is 5040, while the sum is 32.

The square root of 161857031 is about 12722.3044689239. The cubic root of 161857031 is about 544.9757652720.

The spelling of 161857031 in words is "one hundred sixty-one million, eight hundred fifty-seven thousand, thirty-one".