161915939 has 4 divisors (see below), whose sum is σ = 171440424. Its totient is φ = 152391456.

The previous prime is 161915917. The next prime is 161915947. The reversal of 161915939 is 939519161.

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 161915939 - 2²⁴ = 145138723 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161915939.

It is not an unprimeable number, because it can be changed into a prime (161915969) 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, 4762217 + ... + 4762250.

It is an arithmetic number, because the mean of its divisors is an integer number (42860106).

Almost surely, 2^161915939 is an apocalyptic number.

161915939 is a deficient number, since it is larger than the sum of its proper divisors (9524485).

161915939 is an equidigital number, since it uses as much as digits as its factorization.

161915939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9524484.

The product of its digits is 65610, while the sum is 44.

The square root of 161915939 is about 12724.6194049174. The cubic root of 161915939 is about 545.0418720459.

The spelling of 161915939 in words is "one hundred sixty-one million, nine hundred fifteen thousand, nine hundred thirty-nine".