161930091 has 4 divisors (see below), whose sum is σ = 215906792. Its totient is φ = 107953392.

The previous prime is 161930077. The next prime is 161930099. The reversal of 161930091 is 190039161.

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

It is not a de Polignac number, because 161930091 - 2⁵ = 161930059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161930099) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26988346 + ... + 26988351.

It is an arithmetic number, because the mean of its divisors is an integer number (53976698).

Almost surely, 2^161930091 is an apocalyptic number.

161930091 is a deficient number, since it is larger than the sum of its proper divisors (53976701).

161930091 is an equidigital number, since it uses as much as digits as its factorization.

161930091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53976700.

The product of its (nonzero) digits is 1458, while the sum is 30.

The square root of 161930091 is about 12725.1754801260. The cubic root of 161930091 is about 545.0577510836.

The spelling of 161930091 in words is "one hundred sixty-one million, nine hundred thirty thousand, ninety-one".