Alright, let's work through 1638987 times 63253472 step by step
1638987 × 63253472 = 63253472 × (1638987)
+ 63253472 × 7 yielding 442774304
+ 63253472 × 80 resulting in 5060277760
+ 63253472 × 900 which equals 56928124800
+ 63253472 × 8000 that results in 506027776000
+ 63253472 × 30000 which equals 1897604160000
+ 63253472 × 600000 that results in 37952083200000
+ 63253472 × 1000000 what gives us 63253472000000

= 103671618312864
