161215920 has 120 divisors (see below), whose sum is σ = 561536976. Its totient is φ = 42985728.

The previous prime is 161215891. The next prime is 161215933. The reversal of 161215920 is 29512161.

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×161215920² = 51981145722892800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15294 + ... + 23586.

Almost surely, 2^161215920 is an apocalyptic number.

161215920 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 161215920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (280768488).

161215920 is an abundant number, since it is smaller than the sum of its proper divisors (400321056).

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

161215920 is an equidigital number, since it uses as much as digits as its factorization.

161215920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8321 (or 8303 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 27.

The square root of 161215920 is about 12697.0831296011. The cubic root of 161215920 is about 544.2552687504.

The spelling of 161215920 in words is "one hundred sixty-one million, two hundred fifteen thousand, nine hundred twenty".