31372820 has 48 divisors (see below), whose sum is σ = 71115408. Its totient is φ = 11581440.

The previous prime is 31372811. The next prime is 31372889. The reversal of 31372820 is 2827313.

It can be written as a sum of positive squares in 8 ways, for example, as 1056784 + 30316036 = 1028^2 + 5506^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 31372820.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17150 + ... + 18890.

It is an arithmetic number, because the mean of its divisors is an integer number (1481571).

Almost surely, 2^31372820 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31372820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35557704).

31372820 is an abundant number, since it is smaller than the sum of its proper divisors (39742588).

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

31372820 is a wasteful number, since it uses less digits than its factorization.

31372820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1820 (or 1818 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 31372820 is about 5601.1445258983. The cubic root of 31372820 is about 315.3923723896.

The spelling of 31372820 in words is "thirty-one million, three hundred seventy-two thousand, eight hundred twenty".