Alright, let's work through 28007393 times 72857709 step by step
28007393 × 72857709 = 72857709 × (28007393)
+ 72857709 × 3 resulting in 218573127
+ 72857709 × 90 resulting in 6557193810
+ 72857709 × 300 that equals 21857312700
+ 72857709 × 7000 that results in 510003963000
+ 72857709 × 00000 producing 0
+ 72857709 × 000000 yielding 0
+ 72857709 × 8000000 producing 582861672000000
+ 72857709 × 20000000 which equals 1457154180000000

= 2040554489042637
