218 (number) explained

218 (two hundred [and] eighteen) is the natural number following 217 and preceding 219.

In mathematics

• Mertens function (218) = 3, a record high.^[1]
• 218 is nontotient and also noncototient.^[2]
• 218 is the number of inequivalent ways to color the 12 edges of a cube using at most 2 colors, where two colorings are equivalent if they differ only by a rotation of the cube.
• There are 218 nondegenerate Boolean functions of 3 variables.^[3]
• The number of surface points on a 7³ cube.^[4]

In other fields

• 218 is the current number of votes in the US House of Representatives a party or coalition needs to win in order to achieve a majority.^[5]
• The years 218 and 218 BC
• Area code 218, for northern Minnesota.

Notes and References

1. A051400. Smallest value of x such that M(x)=n, where M is Mertens's function.
2. A058763. Integers which are neither totient nor cototient.
3. A000371. A000371. 2022-05-10.
4. 6*n^2 + 2 for n > 0, a(0)=1.
5. News: Why did bail-out pass this time?. 4 October 2008.