Alright, let's work through 87117777 times 78503137 step by step
87117777 × 78503137 = 78503137 × (87117777)
+ 78503137 × 7 that is equal 549521959
+ 78503137 × 70 giving us 5495219590
+ 78503137 × 700 giving us 54952195900
+ 78503137 × 7000 that equals 549521959000
+ 78503137 × 10000 which equals 785031370000
+ 78503137 × 100000 which equals 7850313700000
+ 78503137 × 7000000 resulting in 549521959000000
+ 78503137 × 80000000 what gives us 6280250960000000

= 6839018782966449
