|Cardinal||two hundred sixteen|
(two hundred sixteenth)
|Factorization||23 × 33|
|Divisors||1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 27, 36, 54, 72, 108, 216|
Since 216 = 33 + 43 + 53 = 63, it is the smallest cube that is also the sum of three cubes (Plato was among the first to notice this, and mentioned it in Book VIII of Republic). It is also the sum of a twin prime (107 + 109). 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 p + Tx, where p is 0 or a prime, and Tx = x(x+1)/2 is a triangular number.
In base 10, it is a Harshad number.
216 is a Friedman number.
In other fields
- The 216 colors formed by a 6×6×6 color cube are sometimes known as the web-safe color palette.
- ISO 216 is the ISO's standard for paper sizes.
- 216 is the numerical value of Gevurah, the fifth sephirot in the kabbalistic tree of life, and the sum of the letters in God's 72 hidden names.
- According to the Ken Burns series Baseball, it is the number of stitches on a baseball.
- +216 is the country code of Tunisia.
- (216) is the area code of Cleveland, Ohio, United States.
- The Bayon temple in Cambodia has 216 gigantic smiling faces.
- The year 216
- Wells, D. (1987). The Penguin Dictionary of Curious and Interesting Numbers (p. 144). London: Penguin Group.