31120121220 has 24 divisors (see below), whose sum is σ = 87136339584. Its totient is φ = 8298698976.

The previous prime is 31120121203. The next prime is 31120121231. The reversal of 31120121220 is 2212102113.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 31120121220.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 259334284 + ... + 259334403.

It is an arithmetic number, because the mean of its divisors is an integer number (3630680816).

Almost surely, 2^31120121220 is an apocalyptic number.

31120121220 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31120121220 is an abundant number, since it is smaller than the sum of its proper divisors (56016218364).

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

31120121220 is a wasteful number, since it uses less digits than its factorization.

31120121220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 518668699 (or 518668697 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 31120121220 its reverse (2212102113), we get a palindrome (33332223333).

The spelling of 31120121220 in words is "thirty-one billion, one hundred twenty million, one hundred twenty-one thousand, two hundred twenty".