31131320 has 32 divisors (see below), whose sum is σ = 76414320. Its totient is φ = 11320320.

The previous prime is 31131307. The next prime is 31131323. The reversal of 31131320 is 2313113.

It is a junction number, because it is equal to n+sod(n) for n = 31131295 and 31131304.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31131323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34937 + ... + 35816.

Almost surely, 2^31131320 is an apocalyptic number.

It is an amenable number.

31131320 is an abundant number, since it is smaller than the sum of its proper divisors (45283000).

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

31131320 is a wasteful number, since it uses less digits than its factorization.

31131320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70775 (or 70771 counting only the distinct ones).

The product of its (nonzero) digits is 54, while the sum is 14.

The square root of 31131320 is about 5579.5447842992. The cubic root of 31131320 is about 314.5810168194.

Adding to 31131320 its reverse (2313113), we get a palindrome (33444433).

The spelling of 31131320 in words is "thirty-one million, one hundred thirty-one thousand, three hundred twenty".