MantissaExponent

MantissaExponent[x] gives a list containing the mantissa and exponent of a number x.

MantissaExponent[x,b] gives the base-b mantissa and exponent of x.

Examples

Get the mantissa and exponent of a number:

MantissaExponent[1234.5]
(* {0.12345, 4} *)

Use base 2:

MantissaExponent[8, 2]
(* {0.5, 4} *)

Please visit the official Wolfram Language Reference for more details.