31131213312 has 40 divisors (see below), whose sum is σ = 82935502056. Its totient is φ = 10377070592.

The previous prime is 31131213259. The next prime is 31131213313. The reversal of 31131213312 is 21331213113.

It is a happy number.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31131213313) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10132323 + ... + 10135394.

Almost surely, 2^31131213312 is an apocalyptic number.

31131213312 is a gapful number since it is divisible by the number (32) formed by its first and last digit.

It is an amenable number.

31131213312 is an abundant number, since it is smaller than the sum of its proper divisors (51804288744).

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

31131213312 is an equidigital number, since it uses as much as digits as its factorization.

31131213312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20267738 (or 20267722 counting only the distinct ones).

The product of its digits is 324, while the sum is 21.

Adding to 31131213312 its reverse (21331213113), we get a palindrome (52462426425).

The spelling of 31131213312 in words is "thirty-one billion, one hundred thirty-one million, two hundred thirteen thousand, three hundred twelve".