161791859 has 4 divisors (see below), whose sum is σ = 170307240. Its totient is φ = 153276480.

The previous prime is 161791823. The next prime is 161791901. The reversal of 161791859 is 958197161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 958197161 = 8741 ⋅109621.

It is a cyclic number.

It is not a de Polignac number, because 161791859 - 2²⁰ = 160743283 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161731859) 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, 4257662 + ... + 4257699.

It is an arithmetic number, because the mean of its divisors is an integer number (42576810).

Almost surely, 2^161791859 is an apocalyptic number.

161791859 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

161791859 is a deficient number, since it is larger than the sum of its proper divisors (8515381).

161791859 is an equidigital number, since it uses as much as digits as its factorization.

161791859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8515380.

The product of its digits is 136080, while the sum is 47.

The square root of 161791859 is about 12719.7428826215. The cubic root of 161791859 is about 544.9026103228.

The spelling of 161791859 in words is "one hundred sixty-one million, seven hundred ninety-one thousand, eight hundred fifty-nine".