Alright, let's work through 1623 times 1038 step by step
1623 × 1038 = 1038 × (1623)
+ 1038 × 3 yielding 3114
+ 1038 × 20 resulting in 20760
+ 1038 × 600 producing 622800
+ 1038 × 1000 yielding 1038000

= 1684674
