Alright, let's work through 78872719 times 55438578 step by step
78872719 × 55438578 = 55438578 × (78872719)
+ 55438578 × 9 that is equal 498947202
+ 55438578 × 10 that results in 554385780
+ 55438578 × 700 which equals 38807004600
+ 55438578 × 2000 that results in 110877156000
+ 55438578 × 70000 that is equal 3880700460000
+ 55438578 × 800000 that equals 44350862400000
+ 55438578 × 8000000 that equals 443508624000000
+ 55438578 × 70000000 which equals 3880700460000000

= 4372591384353582
