161510021220 has 48 divisors (see below), whose sum is σ = 454029807168. Its totient is φ = 42897744000.

The previous prime is 161510021213. The next prime is 161510021237. The reversal of 161510021220 is 22120015161.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5347159 + ... + 5377278.

It is an arithmetic number, because the mean of its divisors is an integer number (9458954316).

Almost surely, 2^161510021220 is an apocalyptic number.

161510021220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161510021220 is an abundant number, since it is smaller than the sum of its proper divisors (292519785948).

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

161510021220 is a wasteful number, since it uses less digits than its factorization.

161510021220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10724700 (or 10724698 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 21.

Adding to 161510021220 its reverse (22120015161), we get a palindrome (183630036381).

The spelling of 161510021220 in words is "one hundred sixty-one billion, five hundred ten million, twenty-one thousand, two hundred twenty".