Alright, let's work through 4001 times 2644 step by step
4001 × 2644 = 2644 × (4001)
+ 2644 × 1 that is equal 2644
+ 2644 × 00 giving us 0
+ 2644 × 000 that is equal 0
+ 2644 × 4000 yielding 10576000

= 10578644
