31031131220 has 48 divisors (see below), whose sum is σ = 69026117328. Its totient is φ = 11677655040.

The previous prime is 31031131217. The next prime is 31031131231. The reversal of 31031131220 is 2213113013.

It can be written as a sum of positive squares in 8 ways, for example, as 9453283984 + 21577847236 = 97228^2 + 146894^2 .

It is a super-2 number, since 2×31031131220² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 905600 + ... + 939240.

It is an arithmetic number, because the mean of its divisors is an integer number (1438044111).

Almost surely, 2^31031131220 is an apocalyptic number.

It is an amenable number.

31031131220 is an abundant number, since it is smaller than the sum of its proper divisors (37994986108).

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

31031131220 is a wasteful number, since it uses less digits than its factorization.

31031131220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36380 (or 36378 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 17.

Adding to 31031131220 its reverse (2213113013), we get a palindrome (33244244233).

The spelling of 31031131220 in words is "thirty-one billion, thirty-one million, one hundred thirty-one thousand, two hundred twenty".