Assuming your numbers are in column A ;-
Dim rng As Range
Set rng = Range([A1], [A65536].End(xlUp))
rng.EntireColumn.Insert
With rng.Offset(0, -1)
.FormulaR1C1 = "=IF(RC[1]-INT(RC[1])=0,1,"""")"
On Error Resume Next
.SpecialCells(xlCellTypeFormulas, 2).EntireRow.Delete
On Error GoTo 0
.EntireColumn.Delete
End With