3131121220 has 24 divisors (see below), whose sum is σ = 6589637208. Its totient is φ = 1249728000.

The previous prime is 3131121199. The next prime is 3131121221. The reversal of 3131121220 is 221211313.

It can be written as a sum of positive squares in 4 ways, for example, as 89378116 + 3041743104 = 9454^2 + 55152^2 .

It is a junction number, because it is equal to n+sod(n) for n = 3131121194 and 3131121203.

It is not an unprimeable number, because it can be changed into a prime (3131121221) 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, 160581 + ... + 179020.

It is an arithmetic number, because the mean of its divisors is an integer number (274568217).

Almost surely, 2^3131121220 is an apocalyptic number.

It is an amenable number.

3131121220 is an abundant number, since it is smaller than the sum of its proper divisors (3458515988).

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

3131121220 is a wasteful number, since it uses less digits than its factorization.

3131121220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340071 (or 340069 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 3131121220 is about 55956.4225089489. The cubic root of 3131121220 is about 1462.9628361493.

Adding to 3131121220 its reverse (221211313), we get a palindrome (3352332533).

The spelling of 3131121220 in words is "three billion, one hundred thirty-one million, one hundred twenty-one thousand, two hundred twenty".