18320 has 20 divisors (see below), whose sum is σ = 42780. Its totient is φ = 7296.

The previous prime is 18313. The next prime is 18329. The reversal of 18320 is 2381.

18320 is nontrivially palindromic in base 15.

It can be written as a sum of positive squares in 2 ways, for example, as 12544 + 5776 = 112^2 + 76^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a junction number, because it is equal to n+sod(n) for n = 18295 and 18304.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18329) by changing a digit.

18320 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 3 ways as a sum of consecutive naturals, for example, 35 + ... + 194.

It is an arithmetic number, because the mean of its divisors is an integer number (2139).

2¹⁸³²⁰ is an apocalyptic number.

18320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18320 is an abundant number, since it is smaller than the sum of its proper divisors (24460).

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 (21390).

18320 is a wasteful number, since it uses less digits than its factorization.

18320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242 (or 236 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 18320 is about 135.3513945255. The cubic root of 18320 is about 26.3618058038.

The spelling of 18320 in words is "eighteen thousand, three hundred twenty".