31132820 has 12 divisors (see below), whose sum is σ = 65378964. Its totient is φ = 12453120.

The previous prime is 31132819. The next prime is 31132841. The reversal of 31132820 is 2823113.

It can be written as a sum of positive squares in 2 ways, for example, as 9024016 + 22108804 = 3004^2 + 4702^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 1556641 = 31132820 / (3 + 1 + 1 + 3 + 2 + 8 + 2 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 31132792 and 31132801.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 778301 + ... + 778340.

It is an arithmetic number, because the mean of its divisors is an integer number (5448247).

Almost surely, 2^31132820 is an apocalyptic number.

It is an amenable number.

31132820 is an abundant number, since it is smaller than the sum of its proper divisors (34246144).

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

31132820 is a wasteful number, since it uses less digits than its factorization.

31132820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1556650 (or 1556648 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 31132820 is about 5579.6792022481. The cubic root of 31132820 is about 314.5860692227.

Adding to 31132820 its reverse (2823113), we get a palindrome (33955933).

The spelling of 31132820 in words is "thirty-one million, one hundred thirty-two thousand, eight hundred twenty".