There is no maximum and minimum number, and there is no such thing as maximum and minimum number in the concept of number. However, in the current research, the most significant number is the Greyhound number, which connects each pair of geometric vertices of an n-dimensional hypercube to get a complete graph with 2 n vertices (a simple graph with only one edge between each pair of vertices). Fill each side of the picture with red or blue. Then, the minimum n value that makes all filling methods contain at least one monochromatic complete subgraph at the vertices of four * * * faces is Greer constant. The largest number used in formal mathematical proof is Graham number. It was previously listed in the Guinness Book of World Records and is the largest number in the world.

Ge Henry's number is so huge that it cannot be expressed by scientific notation. Even the exponential tower form like A (B (C (…)) is useless and even mathematicians can't understand it. For example, if all known substances in the universe are converted into ink and put into a pen, there is not enough ink to write all these numbers on paper. But it can be described by Gartner's recursive formula of arrow symbol.

Although this number is too large to be calculated completely, the last few digits of Greyhound number can be deduced by a simple algorithm. Its last 12 bit is 262464 195387.