161561206220 has 48 divisors (see below), whose sum is σ = 357385724640. Its totient is φ = 61180263936.

The previous prime is 161561206207. The next prime is 161561206241. The reversal of 161561206220 is 22602165161.

161561206220 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×161561206220² (a number of 23 digits) contains 22 as substring.

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, 396194 + ... + 692886.

It is an arithmetic number, because the mean of its divisors is an integer number (7445535930).

Almost surely, 2^161561206220 is an apocalyptic number.

161561206220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161561206220 is an abundant number, since it is smaller than the sum of its proper divisors (195824518420).

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

161561206220 is a wasteful number, since it uses less digits than its factorization.

161561206220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 298154 (or 298152 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 32.

The spelling of 161561206220 in words is "one hundred sixty-one billion, five hundred sixty-one million, two hundred six thousand, two hundred twenty".