Trying to write a list of numbers in a cell, keeps converting it to a long number

Hey, I'm doing the website for my company and things have to be entered into the site via spreadsheets. I have a list of numbers

e.g. 3652, 2845, 50925, 4809, 18392

that need to have the spaces removed in order for them to work.

e.g. 3652,2845,50925,4809,18392

There are over 500 cells with multiple numbers in each, so I don't want to do it one at a time, and rightly so, because Excel keeps changing the format and giving me something like

3.6*10^30 and loses all my commas.

Is there an easier way?