Alright, let's work through 80091571 times 78715419 step by step
80091571 × 78715419 = 78715419 × (80091571)
+ 78715419 × 1 that results in 78715419
+ 78715419 × 70 that is equal 5510079330
+ 78715419 × 500 that results in 39357709500
+ 78715419 × 1000 that equals 78715419000
+ 78715419 × 90000 what gives us 7084387710000
+ 78715419 × 000000 giving us 0
+ 78715419 × 0000000 that equals 0
+ 78715419 × 80000000 that equals 6297233520000000

= 6304441569633249
