31820 has 24 divisors (see below), whose sum is σ = 70224. Its totient is φ = 12096.

The previous prime is 31817. The next prime is 31847. The reversal of 31820 is 2813.

31820 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is an Ulam number.

31820 is strictly pandigital in base 6.

It is a nialpdrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 31795 and 31804.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 719 + ... + 761.

It is an arithmetic number, because the mean of its divisors is an integer number (2926).

2³¹⁸²⁰ 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 31820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35112).

31820 is an abundant number, since it is smaller than the sum of its proper divisors (38404).

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

31820 is a wasteful number, since it uses less digits than its factorization.

31820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89 (or 87 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 31820 is about 178.3816134023. The cubic root of 31820 is about 31.6883815357.

It can be divided in two parts, 3 and 1820, that multiplied together give a triangular number (5460 = T₁₀₄).

The spelling of 31820 in words is "thirty-one thousand, eight hundred twenty".