31000221220 has 24 divisors (see below), whose sum is σ = 65103938424. Its totient is φ = 12399426816.

The previous prime is 31000221179. The next prime is 31000221271. The reversal of 31000221220 is 2212200013.

It can be written as a sum of positive squares in 4 ways, for example, as 860483556 + 30139737664 = 29334^2 + 173608^2 .

It is a super-2 number, since 2×31000221220² (a number of 22 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 31000221220.

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, 546934 + ... + 600946.

It is an arithmetic number, because the mean of its divisors is an integer number (2712664101).

Almost surely, 2^31000221220 is an apocalyptic number.

It is an amenable number.

31000221220 is an abundant number, since it is smaller than the sum of its proper divisors (34103717204).

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

31000221220 is a wasteful number, since it uses less digits than its factorization.

31000221220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82719 (or 82717 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

Adding to 31000221220 its reverse (2212200013), we get a palindrome (33212421233).

The spelling of 31000221220 in words is "thirty-one billion, two hundred twenty-one thousand, two hundred twenty".