31312131320 has 128 divisors (see below), whose sum is σ = 74027520000. Its totient is φ = 11907302400.

The previous prime is 31312131317. The next prime is 31312131329. The reversal of 31312131320 is 2313121313.

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 = 31312131292 and 31312131301.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31312131329) 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, 20887931 + ... + 20889429.

It is an arithmetic number, because the mean of its divisors is an integer number (578340000).

Almost surely, 2^31312131320 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 31312131320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37013760000).

31312131320 is an abundant number, since it is smaller than the sum of its proper divisors (42715388680).

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

31312131320 is a wasteful number, since it uses less digits than its factorization.

31312131320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1869 (or 1865 counting only the distinct ones).

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

Adding to 31312131320 its reverse (2313121313), we get a palindrome (33625252633).

The spelling of 31312131320 in words is "thirty-one billion, three hundred twelve million, one hundred thirty-one thousand, three hundred twenty".