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
What Love Is Made Of does best, albeit slightly more polished around the edges". He finally wrote that "the result is more than enough to keep our obsession rolling through yet another summer stretch". Sam Lansky from Idolator believed that the song had potential to become a "club hit" and named it the "biggest thing she’s recorded to date", while like other critics, highlighting Katy's vocals. Commercially, "What Love Is Made Of" fared well on European charts. It stayed two weeks at the UK Singles Chart, where it peaked at number 21. On its component chart, the UK Dance chart, its peak was higher, at