18831 has 4 divisors (see below), whose sum is σ = 25112. Its totient is φ = 12552.

The previous prime is 18803. The next prime is 18839. The reversal of 18831 is 13881.

It is a happy number.

18831 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 18831 - 2¹⁰ = 17807 is a prime.

It is a super-2 number, since 2×18831² = 709213122, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

It is a nialpdrome in base 12.

It is a junction number, because it is equal to n+sod(n) for n = 18798 and 18807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18839) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3136 + ... + 3141.

It is an arithmetic number, because the mean of its divisors is an integer number (6278).

2¹⁸⁸³¹ is an apocalyptic number.

18831 is a deficient number, since it is larger than the sum of its proper divisors (6281).

18831 is an equidigital number, since it uses as much as digits as its factorization.

18831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6280.

The product of its digits is 192, while the sum is 21.

The square root of 18831 is about 137.2260908137. The cubic root of 18831 is about 26.6046649817.

Subtracting from 18831 its reverse (13881), we obtain a triangular number (4950 = T₉₉).

The spelling of 18831 in words is "eighteen thousand, eight hundred thirty-one".