Alright, let's work through 83908308 times 81518628 step by step
83908308 × 81518628 = 81518628 × (83908308)
+ 81518628 × 8 that is equal 652149024
+ 81518628 × 00 yielding 0
+ 81518628 × 300 which equals 24455588400
+ 81518628 × 8000 what gives us 652149024000
+ 81518628 × 00000 which equals 0
+ 81518628 × 900000 that equals 73366765200000
+ 81518628 × 3000000 which equals 244555884000000
+ 81518628 × 80000000 yielding 6521490240000000

= 6840090145961424
