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
Powerful number of "x"+"y"="z" in relatively prime non-cube 3-powerful numbers as follows: the triplet is a solution of the equation 32"X" + 49"Y" = 81"Z". We can construct another solution by setting "X"′ = "X"(49"Y" + 81"Z"), "Y"′ = −"Y"(32"X" + 81"Z"), "Z"′ = "Z"(32"X" − 49"Y") and omitting the common divisor. Powerful number A powerful number is a positive integer "m" such that for every prime number "p" dividing "m", "p" also divides "m". Equivalently, a powerful number is the product of a square and a cube, that is, a number "m" of the form "m" = "a""b", where "a" and