161969920 has 72 divisors (see below), whose sum is σ = 443417184. Its totient is φ = 55529472.

The previous prime is 161969909. The next prime is 161969939. The reversal of 161969920 is 29969161.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 79 + ... + 17998.

It is an arithmetic number, because the mean of its divisors is an integer number (6158572).

Almost surely, 2^161969920 is an apocalyptic number.

161969920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161969920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (221708592).

161969920 is an abundant number, since it is smaller than the sum of its proper divisors (281447264).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161969920 is an equidigital number, since it uses as much as digits as its factorization.

161969920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18105 (or 18091 counting only the distinct ones).

The product of its (nonzero) digits is 52488, while the sum is 43.

The square root of 161969920 is about 12726.7403525019. The cubic root of 161969920 is about 545.1024356455.

The spelling of 161969920 in words is "one hundred sixty-one million, nine hundred sixty-nine thousand, nine hundred twenty".