18321 has 8 divisors (see below), whose sum is σ = 25344. Its totient is φ = 11760.

The previous prime is 18313. The next prime is 18329. The reversal of 18321 is 12381.

It is a happy number.

18321 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (18313) and next prime (18329).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18321 - 2³ = 18313 is a prime.

It is an alternating number because its digits alternate between odd and even.

18321 is an undulating number in base 14.

It is a Curzon number.

It is a plaindrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 18321.

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

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6 + ... + 191.

It is an arithmetic number, because the mean of its divisors is an integer number (3168).

2¹⁸³²¹ is an apocalyptic number.

It is an amenable number.

18321 is a deficient number, since it is larger than the sum of its proper divisors (7023).

18321 is a wasteful number, since it uses less digits than its factorization.

18321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 231.

The product of its digits is 48, while the sum is 15.

The square root of 18321 is about 135.3550885634. The cubic root of 18321 is about 26.3622854495.

Adding to 18321 its sum of digits (15), we get a triangular number (18336 = T₁₉₁).

It can be divided in two parts, 18 and 321, that multiplied together give a triangular number (5778 = T₁₀₇).

The spelling of 18321 in words is "eighteen thousand, three hundred twenty-one".