I'm not aware of any such. Probably best to do the "obvious" thing: factor and clip powers to unity.
squareFreePart[n_Integer] := Times @@ FactorInteger[n][[All, 1]]
squareFreePart[111111111]
(* Out[491]= 37037037 *)
squareFreePart[Times @@ (Range[10]^Range[10])]
(* Out[493]= 210 *)