216 (number)


216 is the natural number following 215 and preceding 217.
Since it is the smallest cube that is also the sum of three cubes. It is also the sum of a twin prime. But since there is no way to express it as the sum of the proper divisors of any other integer, it is an untouchable number.
This multiplicative magic square
has magic constant 216.
It has been conjectured that each natural number not equal to 216 can be written in the form where is or a prime, and is a triangular number.
In base 10, it is a Harshad number.
There are 216 fixed hexominoes, the polyominoes made from 6 squares.
216 is a Friedman number.
216 is the smallest number n, for which n−3, n−2, n−1, n+1, n+2, n+3 are all semiprimes.

In other fields