Răspuns :

U(3⁷¹×4⁶²)=U(3⁷¹)×(4⁶²)=U(3⁶⁸×3³)×U[(4²)³²]=U[(3⁴)¹⁷×27]×U[(4²)³¹]=U(81¹⁷)×U(27)×U(16³¹)=U(1×7×6)=U(42)=2