31021131220 has 24 divisors (see below), whose sum is σ = 67390734600. Its totient is φ = 11980574592.

The previous prime is 31021131179. The next prime is 31021131233. The reversal of 31021131220 is 2213112013.

It can be written as a sum of positive squares in 4 ways, for example, as 185068816 + 30836062404 = 13604^2 + 175602^2 .

It is a junction number, because it is equal to n+sod(n) for n = 31021131194 and 31021131203.

It is a congruent number.

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, 26741775 + ... + 26742934.

It is an arithmetic number, because the mean of its divisors is an integer number (2807947275).

Almost surely, 2^31021131220 is an apocalyptic number.

It is an amenable number.

31021131220 is an abundant number, since it is smaller than the sum of its proper divisors (36369603380).

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

31021131220 is a wasteful number, since it uses less digits than its factorization.

31021131220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53484747 (or 53484745 counting only the distinct ones).

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

Adding to 31021131220 its reverse (2213112013), we get a palindrome (33234243233).

The spelling of 31021131220 in words is "thirty-one billion, twenty-one million, one hundred thirty-one thousand, two hundred twenty".