31020220 has 48 divisors (see below), whose sum is σ = 81220608. Its totient is φ = 9668160.

The previous prime is 31020191. The next prime is 31020221. The reversal of 31020220 is 2202013.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 31020197 and 31020206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31020221) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8532 + ... + 11611.

It is an arithmetic number, because the mean of its divisors is an integer number (1692096).

Almost surely, 2^31020220 is an apocalyptic number.

It is an amenable number.

31020220 is an abundant number, since it is smaller than the sum of its proper divisors (50200388).

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

31020220 is a wasteful number, since it uses less digits than its factorization.

31020220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20170 (or 20168 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 10.

The square root of 31020220 is about 5569.5798764359. The cubic root of 31020220 is about 314.2063500903.

Adding to 31020220 its reverse (2202013), we get a palindrome (33222233).

The spelling of 31020220 in words is "thirty-one million, twenty thousand, two hundred twenty".