161599809 has 16 divisors (see below), whose sum is σ = 250895232. Its totient is φ = 90599808.

The previous prime is 161599799. The next prime is 161599811. The reversal of 161599809 is 908995161.

It is not a de Polignac number, because 161599809 - 2⁵ = 161599777 is a prime.

It is a super-2 number, since 2×161599809² = 52228996537672962, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (161599829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 71484 + ... + 73709.

It is an arithmetic number, because the mean of its divisors is an integer number (15680952).

Almost surely, 2^161599809 is an apocalyptic number.

It is an amenable number.

161599809 is a deficient number, since it is larger than the sum of its proper divisors (89295423).

161599809 is a wasteful number, since it uses less digits than its factorization.

161599809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145256.

The product of its (nonzero) digits is 174960, while the sum is 48.

The square root of 161599809 is about 12712.1913531853. The cubic root of 161599809 is about 544.6869217195.

The spelling of 161599809 in words is "one hundred sixty-one million, five hundred ninety-nine thousand, eight hundred nine".