What is the maximum height UE4 accepts for terrain creation?

I’m creating a map which will reach the bounds of 500kuu length/width (I read that this is the max for playable maps), but i’m short on the info needed to proceed further. In laymans terms, whats the highest height i can make my map? I’m quite new to UE4 and what i read so far about this question is beyond my scope of understanding at the moment. So i was hoping someone could just give me the number in UUs? Thanks!

Side note: I’m going to be importing said terrain from World Machine to 3DS Max to UE4 if this helps.