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
The Carnelian Cube The Carnelian Cube The Carnelian Cube is a fantasy novel by American writers L. Sprague de Camp and Fletcher Pratt. It was first published in hardcover by Gnome Press in 1948, and in paperback by Lancer Books in 1967. An E-book edition was published by Gollancz's SF Gateway imprint on September 29, 2011 as part of a general release of de Camp's works in electronic form. It has also been translated into Italian and German. The carnelian cube of the title is a small red "dream stone" confiscated by archaeologist Arthur Cleveland Finch from Tiridat Ariminian, one of the workers