Alright, let's work through 78002680 times 8545013 step by step
78002680 × 8545013 = 8545013 × (78002680)
+ 8545013 × 0 producing 0
+ 8545013 × 80 that results in 683601040
+ 8545013 × 600 yielding 5127007800
+ 8545013 × 2000 yielding 17090026000
+ 8545013 × 00000 what gives us 0
+ 8545013 × 000000 yielding 0
+ 8545013 × 8000000 what gives us 68360104000000
+ 8545013 × 70000000 that results in 598150910000000

= 666533914634840
