18636 has 12 divisors (see below), whose sum is σ = 43512. Its totient is φ = 6208.

The previous prime is 18617. The next prime is 18637. The reversal of 18636 is 63681.

It is a tau number, because it is divible by the number of its divisors (12).

It is a plaindrome in base 16.

It is a nialpdrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (18637) 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, 765 + ... + 788.

It is an arithmetic number, because the mean of its divisors is an integer number (3626).

2¹⁸⁶³⁶ is an apocalyptic number.

It is an amenable number.

18636 is an abundant number, since it is smaller than the sum of its proper divisors (24876).

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 (21756).

18636 is a wasteful number, since it uses less digits than its factorization.

18636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1560 (or 1558 counting only the distinct ones).

The product of its digits is 864, while the sum is 24.

The square root of 18636 is about 136.5137355727. The cubic root of 18636 is about 26.5125133735.

It can be divided in two parts, 186 and 36, that added together give a palindrome (222).

The spelling of 18636 in words is "eighteen thousand, six hundred thirty-six".