18556 has 6 divisors (see below), whose sum is σ = 32480. Its totient is φ = 9276.

The previous prime is 18553. The next prime is 18583. The reversal of 18556 is 65581.

It is a self number, because there is not a number n which added to its sum of digits gives 18556.

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

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2316 + ... + 2323.

2¹⁸⁵⁵⁶ is an apocalyptic number.

It is an amenable number.

18556 is a deficient number, since it is larger than the sum of its proper divisors (13924).

18556 is a wasteful number, since it uses less digits than its factorization.

18556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4643 (or 4641 counting only the distinct ones).

The product of its digits is 1200, while the sum is 25.

The square root of 18556 is about 136.2204096309. The cubic root of 18556 is about 26.4745216135.

Adding to 18556 its sum of digits (25), we get a palindrome (18581).

The spelling of 18556 in words is "eighteen thousand, five hundred fifty-six".