18956 has 12 divisors (see below), whose sum is σ = 37968. Its totient is φ = 8112.

The previous prime is 18947. The next prime is 18959. The reversal of 18956 is 65981.

18956 = 49² + 50² + ... + 55².

18956 is an admirable number.

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

It is a nialpdrome in base 13.

It is a zygodrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (18959) by changing a digit.

18956 is an untouchable number, because it is not equal to the sum of proper divisors of any 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, 311 + ... + 366.

It is an arithmetic number, because the mean of its divisors is an integer number (3164).

2¹⁸⁹⁵⁶ is an apocalyptic number.

It is an amenable number.

18956 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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 (18984).

18956 is a wasteful number, since it uses less digits than its factorization.

18956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 688 (or 686 counting only the distinct ones).

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

The square root of 18956 is about 137.6807902360. The cubic root of 18956 is about 26.6634023782.

The spelling of 18956 in words is "eighteen thousand, nine hundred fifty-six".