161213220 has 96 divisors (see below), whose sum is σ = 573216000. Its totient is φ = 36847872.

The previous prime is 161213207. The next prime is 161213251. The reversal of 161213220 is 22312161.

161213220 is a `hidden beast` number, since 1 + 612 + 1 + 32 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 161213193 and 161213202.

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, 17545 + ... + 25104.

It is an arithmetic number, because the mean of its divisors is an integer number (5971000).

Almost surely, 2^161213220 is an apocalyptic number.

161213220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161213220 is an abundant number, since it is smaller than the sum of its proper divisors (412002780).

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

161213220 is a wasteful number, since it uses less digits than its factorization.

161213220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42674 (or 42666 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 161213220 is about 12696.9768055234. The cubic root of 161213220 is about 544.2522303875.

Adding to 161213220 its reverse (22312161), we get a palindrome (183525381).

The spelling of 161213220 in words is "one hundred sixty-one million, two hundred thirteen thousand, two hundred twenty".