31213120 has 56 divisors (see below), whose sum is σ = 75127104. Its totient is φ = 12350976.

The previous prime is 31213109. The next prime is 31213129. The reversal of 31213120 is 2131213.

It is a self number, because there is not a number n which added to its sum of digits gives 31213120.

It is not an unprimeable number, because it can be changed into a prime (31213129) 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, 32487 + ... + 33433.

Almost surely, 2^31213120 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 31213120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37563552).

31213120 is an abundant number, since it is smaller than the sum of its proper divisors (43913984).

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

31213120 is a wasteful number, since it uses less digits than its factorization.

31213120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1067 (or 1057 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 31213120 is about 5586.8703224614. The cubic root of 31213120 is about 314.8563046621.

Adding to 31213120 its reverse (2131213), we get a palindrome (33344333).

It can be divided in two parts, 3121 and 3120, that added together give a square (6241 = 79²).

The spelling of 31213120 in words is "thirty-one million, two hundred thirteen thousand, one hundred twenty".