Alright, let's work through 84876721 times 28515057 step by step
84876721 × 28515057 = 28515057 × (84876721)
+ 28515057 × 1 yielding 28515057
+ 28515057 × 20 giving us 570301140
+ 28515057 × 700 producing 19960539900
+ 28515057 × 6000 that equals 171090342000
+ 28515057 × 70000 what gives us 1996053990000
+ 28515057 × 800000 that equals 22812045600000
+ 28515057 × 4000000 resulting in 114060228000000
+ 28515057 × 80000000 that results in 2281204560000000

= 2420264537288097
