31321312 has 48 divisors (see below), whose sum is σ = 68012784. Its totient is φ = 14080000.

The previous prime is 31321309. The next prime is 31321313. The reversal of 31321312 is 21312313.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31321313) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35112 + ... + 35992.

It is an arithmetic number, because the mean of its divisors is an integer number (1416933).

Almost surely, 2^31321312 is an apocalyptic number.

31321312 is a gapful number since it is divisible by the number (32) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31321312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34006392).

31321312 is an abundant number, since it is smaller than the sum of its proper divisors (36691472).

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

31321312 is a wasteful number, since it uses less digits than its factorization.

31321312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1003 (or 995 counting only the distinct ones).

The product of its digits is 108, while the sum is 16.

The square root of 31321312 is about 5596.5446482629. The cubic root of 31321312 is about 315.2196737615.

Adding to 31321312 its reverse (21312313), we get a palindrome (52633625).

It can be divided in two parts, 3132 and 1312, that added together give a palindrome (4444).

The spelling of 31321312 in words is "thirty-one million, three hundred twenty-one thousand, three hundred twelve".