31130220 has 96 divisors (see below), whose sum is σ = 96235776. Its totient is φ = 7456000.

The previous prime is 31130171. The next prime is 31130221. The reversal of 31130220 is 2203113.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 31130196 and 31130205.

It is not an unprimeable number, because it can be changed into a prime (31130221) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 66427 + ... + 66893.

It is an arithmetic number, because the mean of its divisors is an integer number (1002456).

Almost surely, 2^31130220 is an apocalyptic number.

31130220 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31130220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48117888).

31130220 is an abundant number, since it is smaller than the sum of its proper divisors (65105556).

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

31130220 is a wasteful number, since it uses less digits than its factorization.

31130220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 591 (or 589 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 31130220 is about 5579.4462090785. The cubic root of 31130220 is about 314.5773116206.

Adding to 31130220 its reverse (2203113), we get a palindrome (33333333).

The spelling of 31130220 in words is "thirty-one million, one hundred thirty thousand, two hundred twenty".