Board Thread:Questions and Answers/@comment-25526539-20150226010925/@comment-24577221-20150226185237

The apparent coin limit has been discussed a couple of times -- here, for example. Your actual "bank balance" can go much higher than 1,999,999,999 coins; that's just the highest value the game will display. We don't know why that limit is there.

I'm pretty much finished with the game apart from collecting a few more Seasonal monsters, herding the "minions", and tidying up this wiki.