2161220131 has 8 divisors (see below), whose sum is σ = 2470331744. Its totient is φ = 1852200000.

The previous prime is 2161220123. The next prime is 2161220161. The reversal of 2161220131 is 1310221612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 2161220131 - 2³ = 2161220123 is a prime.

It is a super-2 number, since 2×2161220131² = 9341744909279314322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2161220099 and 2161220108.

It is not an unprimeable number, because it can be changed into a prime (2161220111) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38881 + ... + 76381.

It is an arithmetic number, because the mean of its divisors is an integer number (308791468).

Almost surely, 2^2161220131 is an apocalyptic number.

2161220131 is a deficient number, since it is larger than the sum of its proper divisors (309111613).

2161220131 is an equidigital number, since it uses as much as digits as its factorization.

2161220131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45741.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 2161220131 is about 46488.9248208646. The cubic root of 2161220131 is about 1292.9041656623.

Adding to 2161220131 its reverse (1310221612), we get a palindrome (3471441743).

The spelling of 2161220131 in words is "two billion, one hundred sixty-one million, two hundred twenty thousand, one hundred thirty-one".