31090320 has 120 divisors (see below), whose sum is σ = 108084600. Its totient is φ = 7999488.

The previous prime is 31090309. The next prime is 31090337. The reversal of 31090320 is 2309013.

It can be written as a sum of positive squares in 4 ways, for example, as 1016064 + 30074256 = 1008^2 + 5484^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 31090293 and 31090302.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20136 + ... + 21624.

It is an arithmetic number, because the mean of its divisors is an integer number (900705).

Almost surely, 2^31090320 is an apocalyptic number.

31090320 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 31090320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (54042300).

31090320 is an abundant number, since it is smaller than the sum of its proper divisors (76994280).

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

31090320 is a wasteful number, since it uses less digits than its factorization.

31090320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1537 (or 1528 counting only the distinct ones).

The product of its (nonzero) digits is 162, while the sum is 18.

The square root of 31090320 is about 5575.8694389306. The cubic root of 31090320 is about 314.4428549085.

Adding to 31090320 its reverse (2309013), we get a palindrome (33399333).

The spelling of 31090320 in words is "thirty-one million, ninety thousand, three hundred twenty".