31320220 has 24 divisors (see below), whose sum is σ = 65976624. Its totient is φ = 12489216.

The previous prime is 31320217. The next prime is 31320229. The reversal of 31320220 is 2202313.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 31320220.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31320229) 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, 4684 + ... + 9196.

It is an arithmetic number, because the mean of its divisors is an integer number (2749026).

Almost surely, 2^31320220 is an apocalyptic number.

It is an amenable number.

31320220 is an abundant number, since it is smaller than the sum of its proper divisors (34656404).

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

31320220 is a wasteful number, since it uses less digits than its factorization.

31320220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4869 (or 4867 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 31320220 is about 5596.4470872152. The cubic root of 31320220 is about 315.2160103998.

Adding to 31320220 its reverse (2202313), we get a palindrome (33522533).

The spelling of 31320220 in words is "thirty-one million, three hundred twenty thousand, two hundred twenty".