161021580 has 96 divisors (see below), whose sum is σ = 478517760. Its totient is φ = 40343040.

The previous prime is 161021519. The next prime is 161021591. The reversal of 161021580 is 85120161.

It is a self number, because there is not a number n which added to its sum of digits gives 161021580.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 155665 + ... + 156695.

It is an arithmetic number, because the mean of its divisors is an integer number (4984560).

Almost surely, 2^161021580 is an apocalyptic number.

161021580 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 161021580, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (239258880).

161021580 is an abundant number, since it is smaller than the sum of its proper divisors (317496180).

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

161021580 is a wasteful number, since it uses less digits than its factorization.

161021580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1199 (or 1197 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 24.

The square root of 161021580 is about 12689.4278830844. The cubic root of 161021580 is about 544.0364874243.

The spelling of 161021580 in words is "one hundred sixty-one million, twenty-one thousand, five hundred eighty".