31131011320 has 128 divisors (see below), whose sum is σ = 79235884800. Its totient is φ = 10937051136.

The previous prime is 31131011309. The next prime is 31131011323. The reversal of 31131011320 is 2311013113.

It is a junction number, because it is equal to n+sod(n) for n = 31131011294 and 31131011303.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31131011323) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 847659 + ... + 883621.

It is an arithmetic number, because the mean of its divisors is an integer number (619030350).

Almost surely, 2^31131011320 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 31131011320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39617942400).

31131011320 is an abundant number, since it is smaller than the sum of its proper divisors (48104873480).

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

31131011320 is a wasteful number, since it uses less digits than its factorization.

31131011320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36077 (or 36073 counting only the distinct ones).

The product of its (nonzero) digits is 54, while the sum is 16.

Adding to 31131011320 its reverse (2311013113), we get a palindrome (33442024433).

The spelling of 31131011320 in words is "thirty-one billion, one hundred thirty-one million, eleven thousand, three hundred twenty".