Is 2.147483647E9 supposed to be something like 10000000000000000000?

2.147483647E9 represents 2.147483647×10^9 and equals 2147483647 which is the maximum number that an Integer (whole number) can be in Java and is the maximum these config values are set to. This notation is just how it's displayed in the config.

Discord is likely better for questions, but ya forge configs represent large numbers oddly. Beyond that realistically max size is like 200~ish. As those blasts are not very performance but eh... someone has a super computer they can try.