Alright, let's work through 84308240 times 20512321 step by step
84308240 × 20512321 = 20512321 × (84308240)
+ 20512321 × 0 yielding 0
+ 20512321 × 40 yielding 820492840
+ 20512321 × 200 giving us 4102464200
+ 20512321 × 8000 resulting in 164098568000
+ 20512321 × 00000 that is equal 0
+ 20512321 × 300000 giving us 6153696300000
+ 20512321 × 4000000 resulting in 82049284000000
+ 20512321 × 80000000 yielding 1640985680000000

= 1729357681825040
