161660931 has 16 divisors (see below), whose sum is σ = 217267200. Its totient is φ = 106918848.

The previous prime is 161660929. The next prime is 161660957. The reversal of 161660931 is 139066161.

161660931 = 484² + 485² + ... + 842².

It is not a de Polignac number, because 161660931 - 2¹ = 161660929 is a prime.

It is a super-2 number, since 2×161660931² = 52268513223573522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 161660892 and 161660901.

It is not an unprimeable number, because it can be changed into a prime (161660131) 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, 395055 + ... + 395463.

It is an arithmetic number, because the mean of its divisors is an integer number (13579200).

Almost surely, 2^161660931 is an apocalyptic number.

161660931 is a deficient number, since it is larger than the sum of its proper divisors (55606269).

161660931 is a wasteful number, since it uses less digits than its factorization.

161660931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1138.

The product of its (nonzero) digits is 5832, while the sum is 33.

The square root of 161660931 is about 12714.5951960729. The cubic root of 161660931 is about 544.7555854919.

The spelling of 161660931 in words is "one hundred sixty-one million, six hundred sixty thousand, nine hundred thirty-one".