31890 has 16 divisors (see below), whose sum is σ = 76608. Its totient is φ = 8496.

The previous prime is 31883. The next prime is 31891. The reversal of 31890 is 9813.

31890 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is a nialpdrome in base 8.

It is not an unprimeable number, because it can be changed into a prime (31891) by changing a digit.

31890 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 502 + ... + 561.

It is an arithmetic number, because the mean of its divisors is an integer number (4788).

2³¹⁸⁹⁰ is an apocalyptic number.

31890 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

31890 is an abundant number, since it is smaller than the sum of its proper divisors (44718).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38304).

31890 is a wasteful number, since it uses less digits than its factorization.

31890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1073.

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 31890 is about 178.5777141751. The cubic root of 31890 is about 31.7116013357.

The spelling of 31890 in words is "thirty-one thousand, eight hundred ninety".