18390 has 16 divisors (see below), whose sum is σ = 44208. Its totient is φ = 4896.

The previous prime is 18379. The next prime is 18397. The reversal of 18390 is 9381.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18397) by changing a digit.

18390 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, 277 + ... + 336.

It is an arithmetic number, because the mean of its divisors is an integer number (2763).

2¹⁸³⁹⁰ is an apocalyptic number.

18390 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18390 is an abundant number, since it is smaller than the sum of its proper divisors (25818).

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 (22104).

18390 is a wasteful number, since it uses less digits than its factorization.

18390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 623.

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

The square root of 18390 is about 135.6097341639. The cubic root of 18390 is about 26.3953389384.

Subtracting from 18390 its reverse (9381), we obtain a palindrome (9009).

The spelling of 18390 in words is "eighteen thousand, three hundred ninety".