161721867844 has 12 divisors (see below), whose sum is σ = 283128943104. Its totient is φ = 80827884104.

The previous prime is 161721867823. The next prime is 161721867851. The reversal of 161721867844 is 448768127161.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8251444 + ... + 8271019.

It is an arithmetic number, because the mean of its divisors is an integer number (23594078592).

Almost surely, 2^161721867844 is an apocalyptic number.

It is an amenable number.

161721867844 is a deficient number, since it is larger than the sum of its proper divisors (121407075260).

161721867844 is a wasteful number, since it uses less digits than its factorization.

161721867844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16524914 (or 16524912 counting only the distinct ones).

The product of its digits is 3612672, while the sum is 55.

The spelling of 161721867844 in words is "one hundred sixty-one billion, seven hundred twenty-one million, eight hundred sixty-seven thousand, eight hundred forty-four".