18659 has 4 divisors (see below), whose sum is σ = 19104. Its totient is φ = 18216.

The previous prime is 18637. The next prime is 18661. The reversal of 18659 is 95681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 95681 = 163 ⋅587.

It is a cyclic number.

It is not a de Polignac number, because 18659 - 2¹² = 14563 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a nialpdrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (18679) 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 3 ways as a sum of consecutive naturals, for example, 152 + ... + 245.

It is an arithmetic number, because the mean of its divisors is an integer number (4776).

2¹⁸⁶⁵⁹ is an apocalyptic number.

18659 is a deficient number, since it is larger than the sum of its proper divisors (445).

18659 is an equidigital number, since it uses as much as digits as its factorization.

18659 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 444.

The product of its digits is 2160, while the sum is 29.

The square root of 18659 is about 136.5979502042. The cubic root of 18659 is about 26.5234158761.

The spelling of 18659 in words is "eighteen thousand, six hundred fifty-nine".