I would take a slightly different way
(defun chcx (x / sobject)
(if (setq sobject (entsel "\nPick a object ")) ;if something selected change prop
(command "chprop" sobject "" "c" x "LT" "Divide2" "")
)
(princ)
)
To run type (chcx 6) on command line, yes could do a select color also or make lots of defuns CHC6 CHC4 and so on.