[math-fun] Characterization of irrationals x such that {frac(n!*x)} is dense in [0, 1) ?

Is there a characterization of irrationals x such that {frac(n! * x) : n = 1,2,3,...} is dense in [0,1) ? Do almost all irrationals satisfy this condition? --Dan _____________________________________________________________________ "It don't mean a thing if it ain't got that certain je ne sais quoi." --Peter Schickele