IntegerExponent

IntegerExponent[n, b] gives the highest power of b that divides n.

Examples

Power of 2 in 24:

IntegerExponent[24, 2]
(* 3 *)

Power of 5 in 1000:

IntegerExponent[1000, 5]
(* 3 *)

Please visit the official Wolfram Language Reference for more details.