Rounding large exponential numbers e.g. (6.624147...e+25 to 6.62e+25)
I think, if I understand your problem correctly, you could use float("%.2e" % x)
This just converts the value to text, in exponential format, with two fractional places (so 'pi' would become "3.14e+00"), and then converts that back to float. It will work with your example, and with small numbers like 5.42242344e-30
For python 3.6+, it's better to use float(f"{x:.2e}") - thanks @gabriel-jablonski
I have a list of very large numbers I need to round. 
For example:
6.624147027484989e+25 I need to round to 6.62e25.
However, np.around, math.ceiling, round(), etc... are not working. I'm thinking because instead of round 6.624147027484989e+25 to 6.62e25, it's just making it an integer while I actually need to make the entire number much smaller... if that makes sense.