18559 has 4 divisors (see below), whose sum is σ = 18904. Its totient is φ = 18216.

The previous prime is 18553. The next prime is 18583. The reversal of 18559 is 95581.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18559 - 2⁹ = 18047 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18553) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72 + ... + 205.

It is an arithmetic number, because the mean of its divisors is an integer number (4726).

2¹⁸⁵⁵⁹ is an apocalyptic number.

18559 is a deficient number, since it is larger than the sum of its proper divisors (345).

18559 is an equidigital number, since it uses as much as digits as its factorization.

18559 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344.

The product of its digits is 1800, while the sum is 28.

The square root of 18559 is about 136.2314207516. The cubic root of 18559 is about 26.4759482731.

The spelling of 18559 in words is "eighteen thousand, five hundred fifty-nine".