64 (number) 64 (number) 64 (sixty-four) is the natural number following 63 and preceding 65. Sixty-four is the square of 8, the cube of 4, and the sixth power of 2. It is the smallest number with exactly seven divisors. It is the lowest positive power of two that is adjacent to neither a Mersenne prime nor a Fermat prime. 64 is the sum of Euler's totient function for the first fourteen integers. It is also a dodecagonal number and a centered triangular number. 64 is also the first whole number that is both a perfect square and a perfect cube. Since
Dino Cube first mass-produced version had pictures of dinosaurs depicted on each piece, which led to the adoption of the puzzle's current name of "Dino Cube". It is not known what the puzzle had been called before this dinosaur version was introduced. The later versions, however, adopted the practice of using standard single-colour stickers, in common with most other twisty puzzles. The Dino Cube is a twisty puzzle in the shape of a cube. It consists of 12 movable pieces, all of which are located on the edges of the cube. The puzzle can be thought of as twisting around its corners: