I have a 186 page PDF document. It's for a class we teach. We found that putting in dividers with the stickies to be more expensive than we'd like. After a survey we found most ppl want to see pg numbers.

I'd like a program that will automatically put the pg numbers on the exact same place on each page automatically. Basing it on the exact place I choose to put the first one. I'd like the ability to zoom in and drag it if I need to even after I have the program automatically add them for me(incase some may not be visible due to Pre-existing text or color). Is this possible on the iPhone or iMac?

Try enolsoft pdf to text.
Personal suggestion.