31130221220 has 96 divisors (see below), whose sum is σ = 75853241856. Its totient is φ = 10510617600.

The previous prime is 31130221201. The next prime is 31130221223. The reversal of 31130221220 is 2212203113.

It is a super-2 number, since 2×31130221220² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (31130221223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13646480 + ... + 13648760.

It is an arithmetic number, because the mean of its divisors is an integer number (790137936).

Almost surely, 2^31130221220 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31130221220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37926620928).

31130221220 is an abundant number, since it is smaller than the sum of its proper divisors (44723020636).

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

31130221220 is a wasteful number, since it uses less digits than its factorization.

31130221220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3741 (or 3739 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 31130221220 its reverse (2212203113), we get a palindrome (33342424333).

The spelling of 31130221220 in words is "thirty-one billion, one hundred thirty million, two hundred twenty-one thousand, two hundred twenty".