Alright, let's work through 78921084 times 61379768 step by step
78921084 × 61379768 = 61379768 × (78921084)
+ 61379768 × 4 resulting in 245519072
+ 61379768 × 80 that is equal 4910381440
+ 61379768 × 000 producing 0
+ 61379768 × 1000 resulting in 61379768000
+ 61379768 × 20000 giving us 1227595360000
+ 61379768 × 900000 what gives us 55241791200000
+ 61379768 × 8000000 that results in 491038144000000
+ 61379768 × 70000000 giving us 4296583760000000

= 4844157826228512
