Alright, let's work through 3604 times 5409 step by step
3604 × 5409 = 5409 × (3604)
+ 5409 × 4 producing 21636
+ 5409 × 00 that equals 0
+ 5409 × 600 giving us 3245400
+ 5409 × 3000 giving us 16227000

= 19494036
