Alright, let's work through 81371121 times 76300291 step by step
81371121 × 76300291 = 76300291 × (81371121)
+ 76300291 × 1 that is equal 76300291
+ 76300291 × 20 giving us 1526005820
+ 76300291 × 100 what gives us 7630029100
+ 76300291 × 1000 that results in 76300291000
+ 76300291 × 70000 resulting in 5341020370000
+ 76300291 × 300000 resulting in 22890087300000
+ 76300291 × 1000000 that results in 76300291000000
+ 76300291 × 80000000 giving us 6104023280000000

= 6208640211296211
