Alright, let's work through 83921383 times 16115162 step by step
83921383 × 16115162 = 16115162 × (83921383)
+ 16115162 × 3 yielding 48345486
+ 16115162 × 80 that results in 1289212960
+ 16115162 × 300 yielding 4834548600
+ 16115162 × 1000 yielding 16115162000
+ 16115162 × 20000 producing 322303240000
+ 16115162 × 900000 that results in 14503645800000
+ 16115162 × 3000000 which equals 48345486000000
+ 16115162 × 80000000 which equals 1289212960000000

= 1352406682309046
