31221220220 has 24 divisors (see below), whose sum is σ = 65682296064. Its totient is φ = 12466062656.

The previous prime is 31221220181. The next prime is 31221220237. The reversal of 31221220220 is 2202212213.

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, 1390172 + ... + 1412451.

It is an arithmetic number, because the mean of its divisors is an integer number (2736762336).

Almost surely, 2^31221220220 is an apocalyptic number.

It is an amenable number.

31221220220 is an abundant number, since it is smaller than the sum of its proper divisors (34461075844).

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

31221220220 is a wasteful number, since it uses less digits than its factorization.

31221220220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2803189 (or 2803187 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

Adding to 31221220220 its reverse (2202212213), we get a palindrome (33423432433).

The spelling of 31221220220 in words is "thirty-one billion, two hundred twenty-one million, two hundred twenty thousand, two hundred twenty".