6000000edo
The 6 million divisions of the octave divides the 2/1 into steps of exactly 0.0002 cent, or 200 microcent each.
While this system is absurdly large for any human application, from a technical standpoint it is the only one that rightfully bears the name microtonal, since it divides a tone, which is 1/6th of an octave, into 1'000'000 steps, and the SI prefix "micro-" denotes division of a unit into 1 million parts.