18840 has 32 divisors (see below), whose sum is σ = 56880. Its totient is φ = 4992.

The previous prime is 18839. The next prime is 18859. The reversal of 18840 is 4881.

It is a nialpdrome in base 12 and base 13.

It is a congruent number.

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, 42 + ... + 198.

2¹⁸⁸⁴⁰ is an apocalyptic number.

18840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28440).

18840 is an abundant number, since it is smaller than the sum of its proper divisors (38040).

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

18840 is a wasteful number, since it uses less digits than its factorization.

18840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171 (or 167 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 21.

The square root of 18840 is about 137.2588794942. The cubic root of 18840 is about 26.6089027430.

It can be divided in two parts, 18 and 840, that added together give a palindrome (858).

The spelling of 18840 in words is "eighteen thousand, eight hundred forty".