31113021220 has 12 divisors (see below), whose sum is σ = 65337344604. Its totient is φ = 12445208480.

The previous prime is 31113021197. The next prime is 31113021221. The reversal of 31113021220 is 2212031113.

It can be written as a sum of positive squares in 2 ways, for example, as 19931227684 + 11181793536 = 141178^2 + 105744^2 .

It is a junction number, because it is equal to n+sod(n) for n = 31113021194 and 31113021203.

It is not an unprimeable number, because it can be changed into a prime (31113021221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 777825511 + ... + 777825550.

It is an arithmetic number, because the mean of its divisors is an integer number (5444778717).

Almost surely, 2^31113021220 is an apocalyptic number.

It is an amenable number.

31113021220 is an abundant number, since it is smaller than the sum of its proper divisors (34224323384).

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

31113021220 is a wasteful number, since it uses less digits than its factorization.

31113021220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1555651070 (or 1555651068 counting only the distinct ones).

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

Adding to 31113021220 its reverse (2212031113), we get a palindrome (33325052333).

The spelling of 31113021220 in words is "thirty-one billion, one hundred thirteen million, twenty-one thousand, two hundred twenty".