31131133220 has 48 divisors (see below), whose sum is σ = 71797320000. Its totient is φ = 11244424320.

The previous prime is 31131133219. The next prime is 31131133283. The reversal of 31131133220 is 2233113113.

It is a super-2 number, since 2×31131133220² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 31131133192 and 31131133201.

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, 442070 + ... + 507629.

It is an arithmetic number, because the mean of its divisors is an integer number (1495777500).

Almost surely, 2^31131133220 is an apocalyptic number.

It is an amenable number.

31131133220 is an abundant number, since it is smaller than the sum of its proper divisors (40666186780).

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

31131133220 is a wasteful number, since it uses less digits than its factorization.

31131133220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 949868 (or 949866 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 20.

Adding to 31131133220 its reverse (2233113113), we get a palindrome (33364246333).

The spelling of 31131133220 in words is "thirty-one billion, one hundred thirty-one million, one hundred thirty-three thousand, two hundred twenty".