31520 has 24 divisors (see below), whose sum is σ = 74844. Its totient is φ = 12544.

The previous prime is 31517. The next prime is 31531. The reversal of 31520 is 2513.

31520 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 29584 + 1936 = 172^2 + 44^2 .

31520 is an undulating number in base 14.

31520 is strictly pandigital in base 6.

It is a plaindrome in base 13.

It is a nialpdrome in base 8.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 31520.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 62 + ... + 258.

2³¹⁵²⁰ 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 31520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37422).

31520 is an abundant number, since it is smaller than the sum of its proper divisors (43324).

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

31520 is a wasteful number, since it uses less digits than its factorization.

31520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212 (or 204 counting only the distinct ones).

The product of its (nonzero) digits is 30, while the sum is 11.

The square root of 31520 is about 177.5387281694. The cubic root of 31520 is about 31.5884805526.

It can be divided in two parts, 3 and 1520, that multiplied together give a triangular number (4560 = T₉₅).

The spelling of 31520 in words is "thirty-one thousand, five hundred twenty".