How to write an incremental game? (dealing with extremely large numbers)

Hi every one! I have discovered games called “Incremental games”, and I have seen how they can be extremely addicting. I have played a few and I have seen this can be a good project to start. But there is a problem though. How do those games deal with insanely large values like for example “1.0+E91011” or " Trenonagintillion"? I have tried to google but not gotten any answers that I could use, and most of what I could find was for the “Unity 3D” engine which I don’t like to use. I prefer Unreal. There are plenty of such games out there for many platforms. Including Flash. How do the developers manage this large numbers? From what I managed to research though, I guess they are doing something to make it look like large numbers, but I am not sure. I found a forum where someone wanted to cheat in a game called “Time clickers” and the response they got claimed that the game makers had made it impossible to cheat, but I don’t think so, I think the values must be held in such a way to manage extremely large values and no “cheat tools” will be able to detect them. But it cannot be a secret on how to be able to use this gigantic numbers system since there are quite a lot of games like this out there. Anyone who knows where to start?

It’s just multiple integers glued together.