31312220 has 12 divisors (see below), whose sum is σ = 65755704. Its totient is φ = 12524880.

The previous prime is 31312219. The next prime is 31312243. The reversal of 31312220 is 2221313.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 31312195 and 31312204.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 782786 + ... + 782825.

It is an arithmetic number, because the mean of its divisors is an integer number (5479642).

Almost surely, 2^31312220 is an apocalyptic number.

It is an amenable number.

31312220 is an abundant number, since it is smaller than the sum of its proper divisors (34443484).

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

31312220 is a wasteful number, since it uses less digits than its factorization.

31312220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1565620 (or 1565618 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 31312220 is about 5595.7323023890. The cubic root of 31312220 is about 315.1891699879.

Adding to 31312220 its reverse (2221313), we get a palindrome (33533533).

The spelling of 31312220 in words is "thirty-one million, three hundred twelve thousand, two hundred twenty".