31121011220 has 48 divisors (see below), whose sum is σ = 71064739200. Its totient is φ = 11379263616.

The previous prime is 31121011219. The next prime is 31121011247. The reversal of 31121011220 is 2211012113.

It is a junction number, because it is equal to n+sod(n) for n = 31121011195 and 31121011204.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 554270 + ... + 607829.

It is an arithmetic number, because the mean of its divisors is an integer number (1480515400).

Almost surely, 2^31121011220 is an apocalyptic number.

It is an amenable number.

31121011220 is an abundant number, since it is smaller than the sum of its proper divisors (39943727980).

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

31121011220 is a wasteful number, since it uses less digits than its factorization.

31121011220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1162224 (or 1162222 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 31121011220 its reverse (2211012113), we get a palindrome (33332023333).

The spelling of 31121011220 in words is "thirty-one billion, one hundred twenty-one million, eleven thousand, two hundred twenty".