Alright, let's work through 1639 times 2408 step by step
1639 × 2408 = 2408 × (1639)
+ 2408 × 9 yielding 21672
+ 2408 × 30 giving us 72240
+ 2408 × 600 yielding 1444800
+ 2408 × 1000 that results in 2408000

= 3946712
