31806 has 32 divisors (see below), whose sum is σ = 76800. Its totient is φ = 9720.

The previous prime is 31799. The next prime is 31817. The reversal of 31806 is 60813.

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

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 31806.

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, 1011 + ... + 1041.

It is an arithmetic number, because the mean of its divisors is an integer number (2400).

2³¹⁸⁰⁶ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31806, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38400).

31806 is an abundant number, since it is smaller than the sum of its proper divisors (44994).

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

31806 is a wasteful number, since it uses less digits than its factorization.

31806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61 (or 55 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 31806 is about 178.3423673724. The cubic root of 31806 is about 31.6837334902.

The spelling of 31806 in words is "thirty-one thousand, eight hundred six".