64 (number) it is possible to find sequences of 64 consecutive integers such that each inner member shares a factor with either the first or the last member, 64 is an Erdős–Woods number. In base 10, no integer added up to its own digits yields 64, hence it is a self number. 64 is a superperfect number—a number such that σ(σ("n")) = 2"n". 64 is the index of Graham's number in the rapidly growing sequence 3↑↑↑↑3, 3 ↑ 3,… Sixty-four is: 64 (number) 64 (sixty-four) is the natural number following 63 and preceding 65. Sixty-four is the square of 8, the cube
Squaring the square and "R"'s smallest edge square is adjacent to smaller squares not on the edge. Therefore, the smallest square "s" in "R" is surrounded by "larger", and therefore "higher", cubes on all four sides. Hence the upper face of the cube on "s" is divided into a perfect squared square by the cubes which rest on it. Let "s" be the smallest square in this dissection. The sequence of squares "s", "s", ... is infinite and the corresponding cubes are infinite in number. This contradicts our original supposition. If a 4-dimensional hypercube could be perfectly hypercubed then its 'faces' would be