BigNum:format(type,precision)

Return a string representation of the BigNum value.

The type argument can be one of 'e', 'g', or 'x'

e	Use scientific format, example: 1.2345678901234e18
gUse fixed format, example: 123456789.012345
xUse hexadecimal format, example: 0x1.2d687e3df217cec28a18p+20

The precision argument determines the maximum number of characters which are used to output the number.