When you animate, Maya needs to keep track of the timing of keys. Maya internally converts each frame's time value to a 64-bit whole number representation, which is called a tick.
Ticks are the smallest increment of time in Maya and each represents 1/ 141,120,000 of a second. This means that Maya counts 141,120,000 ticks per second (tps), at a rate of 24 frames per second (fps) – that's 5,880,000 ticks per frame (tpf).
For example, at 15 fps, you have 9,408,000 tpf (141,120,000/15).
However, the Maya tick is so small (1/141,120,000th of a second) that it is extremely precise even when you use fractional frame rates (such as 24.976 or 29.97 fps).
In order to be backward-compatible, we recommend that you save your scenes as Maya ASCII (.ma) files. Since Maya 2018, binary files are saved in 64bit format, which makes Maya binary files (*.mb) incompatible with earlier versions of Maya.