Alright, let's work through 3447 times 3603 step by step
3447 × 3603 = 3603 × (3447)
+ 3603 × 7 that is equal 25221
+ 3603 × 40 that is equal 144120
+ 3603 × 400 that equals 1441200
+ 3603 × 3000 yielding 10809000

= 12419541
