621 (DCXXI) ebile ngwaga wa go thoma ka Mošupologo, ngwaga wa bobedi ngwagengsome wa 620s, ngwaga wa bomasomepedi tee ngwagengkgolo wa Ngwagakgolo 7, le ngwaga wa bomakgolo tshela masomepedi tee ngwagengkete wa Ngwagakete 1.