The precision of floating-point numbers is variable. The larger the number, the smaller the decimal precision. However, even for numbers around 0 there is not nearly enough precision to do any sort of operations with the numbers you are talking about.
You can try doing all your calculations using doubles and then transfer the final calculated values to the Unreal engine which uses floats, but if the final values also require extremely high precision this won’t really work either. Instead you’ll need to do some scaling. What you’ll want to do is pick a reasonable fixed scale like x100 or x1000. All values being fed into the engine should use this scale. You can do your high precision calculations using doubles and then apply the scaling and map those values to unreal. If you need even more precision than double (which is certainly possible) then you may need to bring in a scientific math library which can do the low-level, super-high-precision math for you, then use the scaling trick when converting them to values that unreal can use.