18656 has 24 divisors (see below), whose sum is σ = 40824. Its totient is φ = 8320.

The previous prime is 18637. The next prime is 18661. The reversal of 18656 is 65681.

It is a super-3 number, since 3×18656³ = 19479457333248, which contains 333 as substring.

It is a nialpdrome in base 13.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 18656.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 326 + ... + 378.

It is an arithmetic number, because the mean of its divisors is an integer number (1701).

2¹⁸⁶⁵⁶ is an apocalyptic number.

18656 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20412).

18656 is an abundant number, since it is smaller than the sum of its proper divisors (22168).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18656 is a wasteful number, since it uses less digits than its factorization.

With its predecessor (18655) it forms a Ruth-Aaron pair, since the sum of their distinct prime factors is the same (66).

18656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74 (or 66 counting only the distinct ones).

The product of its digits is 1440, while the sum is 26.

The square root of 18656 is about 136.5869686317. The cubic root of 18656 is about 26.5219943188.

It can be divided in two parts, 186 and 56, that added together give a palindrome (242).

The spelling of 18656 in words is "eighteen thousand, six hundred fifty-six".