Just in case you cannot tell, the exact number is exactly in between the two inexact results:
> (- 13407807929942598588139732355608757972494524375225679733981068131349151486565474898751136354405850399729303719974268319295398132445078977825297784408899584 (inexact->exact 1.3407807929942597e154)) 1488565707357402911845015158554633286356257506687627387456491927921949262056238946972039271861787782268441644249633132407878864135402815488 > (- (inexact->exact 1.34078079299426e154) 13407807929942598588139732355608757972494524375225679733981068131349151486565474898751136354405850399729303719974268319295398132445078977825297784408899584) 1488565707357402911845015158554633286356257506687627387456491927921949262056238946972039271861787782268441644249633132407878864135402815488
Just in case you cannot tell, the exact number is exactly in between the two inexact results:
> (- 134078079299425 985881397323556 087579724945243 752256797339810 681313491514865 654748987511363 544058503997293 037199742683192 953981324450789 778252977844088 99584 (inexact->exact 1.3407807929942 597e154) ) 291184501515855 463328635625750 668762738745649 192792194926205 623894697203927 186178778226844 164424963313240 787886413540281 5488 6e154) 134078079299425 985881397323556 087579724945243 752256797339810 681313491514865 654748987511363 544058503997293 037199742683192 953981324450789 778252977844088 99584) 291184501515855 463328635625750 668762738745649 192792194926205 623894697203927 186178778226844 164424963313240 787886413540281 5488
148856570735740
> (- (inexact->exact 1.3407807929942
148856570735740