161931290 has 32 divisors (see below), whose sum is σ = 318587904. Its totient is φ = 58993920.

The previous prime is 161931283. The next prime is 161931311. The reversal of 161931290 is 92139161.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10094 + ... + 20633.

It is an arithmetic number, because the mean of its divisors is an integer number (9955872).

Almost surely, 2^161931290 is an apocalyptic number.

161931290 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

161931290 is a deficient number, since it is larger than the sum of its proper divisors (156656614).

161931290 is a wasteful number, since it uses less digits than its factorization.

161931290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30782.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 161931290 is about 12725.2225913734. Note that the first 3 decimals coincide. The cubic root of 161931290 is about 545.0590963609.

The spelling of 161931290 in words is "one hundred sixty-one million, nine hundred thirty-one thousand, two hundred ninety".