18385 has 4 divisors (see below), whose sum is σ = 22068.
Its totient is φ = 14704.
The previous prime is 18379. The next prime is 18397. The reversal of 18385 is 58381.
18385 is nontrivially palindromic in base 4.
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58381 = 79 ⋅739.
It can be written as a sum of positive squares in 2 ways, for example, as 10816 + 7569 = 104^2 + 87^2
It is a cyclic number.
It is not a de Polignac number, because 18385 - 25 = 18353 is a prime.
It is an alternating number because its digits alternate between odd and even.
It is a Duffinian number.
It is a plaindrome in base 15.
It is an unprimeable number.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1834 + ... + 1843.
It is an arithmetic number, because the mean of its divisors is an integer number (5517).
218385 is an apocalyptic number.
It is an amenable number.
18385 is a deficient number, since it is larger than the sum of its proper divisors (3683).
18385 is an equidigital number, since it uses as much as digits as its factorization.
18385 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 3682.
The product of its digits is 960, while the sum is 25.
The square root of 18385 is about 135.5912976559.
The cubic root of 18385 is about 26.3929465393.
The spelling of 18385 in words is "eighteen thousand, three hundred eighty-five".