161937931 has 4 divisors (see below), whose sum is σ = 170461000. Its totient is φ = 153414864.

The previous prime is 161937887. The next prime is 161937953. The reversal of 161937931 is 139739161.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 161937931 - 2⁷ = 161937803 is a prime.

It is a super-2 number, since 2×161937931² = 52447786993121522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161937961) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4261506 + ... + 4261543.

It is an arithmetic number, because the mean of its divisors is an integer number (42615250).

Almost surely, 2^161937931 is an apocalyptic number.

161937931 is a deficient number, since it is larger than the sum of its proper divisors (8523069).

161937931 is an equidigital number, since it uses as much as digits as its factorization.

161937931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8523068.

The product of its digits is 30618, while the sum is 40.

The square root of 161937931 is about 12725.4835271592. The cubic root of 161937931 is about 545.0665474388.

The spelling of 161937931 in words is "one hundred sixty-one million, nine hundred thirty-seven thousand, nine hundred thirty-one".