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
Square-free integer square-free factors that are naturally associated to every integer: the square-free part, the above factor , and the largest square-free factor. Each is a factor of the next one. All are easily deduced from a prime factorization: if is the prime factorization of , where formula_3 are distinct prime numbers, then the square-free part is The square-free factor such the quotient is a square is and the largest square-free factor is For example, if formula_7 the square-free part is , the square-free factor such that the quotient is a square is , and the largest square-free factor is . No