31530220 has 12 divisors (see below), whose sum is σ = 66213504. Its totient is φ = 12612080.

The previous prime is 31530211. The next prime is 31530269. The reversal of 31530220 is 2203513.

It is a junction number, because it is equal to n+sod(n) for n = 31530194 and 31530203.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 788236 + ... + 788275.

It is an arithmetic number, because the mean of its divisors is an integer number (5517792).

Almost surely, 2^31530220 is an apocalyptic number.

It is an amenable number.

31530220 is an abundant number, since it is smaller than the sum of its proper divisors (34683284).

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

31530220 is a wasteful number, since it uses less digits than its factorization.

31530220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1576520 (or 1576518 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 16.

The square root of 31530220 is about 5615.1776463439. The cubic root of 31530220 is about 315.9189425168.

Adding to 31530220 its reverse (2203513), we get a palindrome (33733733).

The spelling of 31530220 in words is "thirty-one million, five hundred thirty thousand, two hundred twenty".