18240 has 56 divisors (see below), whose sum is σ = 60960. Its totient is φ = 4608.

The previous prime is 18233. The next prime is 18251. The reversal of 18240 is 4281.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 951 + ... + 969.

2¹⁸²⁴⁰ is an apocalyptic number.

18240 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 18240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30480).

18240 is an abundant number, since it is smaller than the sum of its proper divisors (42720).

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

18240 is a wasteful number, since it uses less digits than its factorization.

18240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39 (or 29 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 18240 is about 135.0555441291. The cubic root of 18240 is about 26.3233774610.

Subtracting from 18240 its sum of digits (15), we obtain a square (18225 = 135²).

It can be divided in two parts, 182 and 40, that added together give a palindrome (222).

The spelling of 18240 in words is "eighteen thousand, two hundred forty".