31331320 has 16 divisors (see below), whose sum is σ = 70495560. Its totient is φ = 12532512.

The previous prime is 31331317. The next prime is 31331327. The reversal of 31331320 is 2313313.

It is a super-2 number, since 2×31331320² = 1963303225884800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31331294 and 31331303.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31331327) 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, 391602 + ... + 391681.

Almost surely, 2^31331320 is an apocalyptic number.

It is an amenable number.

31331320 is an abundant number, since it is smaller than the sum of its proper divisors (39164240).

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

31331320 is a wasteful number, since it uses less digits than its factorization.

31331320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 783294 (or 783290 counting only the distinct ones).

The product of its (nonzero) digits is 162, while the sum is 16.

The square root of 31331320 is about 5597.4386999770. The cubic root of 31331320 is about 315.2532439021.

Adding to 31331320 its reverse (2313313), we get a palindrome (33644633).

The spelling of 31331320 in words is "thirty-one million, three hundred thirty-one thousand, three hundred twenty".