Alright, let's work through 4327 times 3603 step by step
4327 × 3603 = 3603 × (4327)
+ 3603 × 7 yielding 25221
+ 3603 × 20 producing 72060
+ 3603 × 300 which equals 1080900
+ 3603 × 4000 yielding 14412000

= 15590181
