Alright, let's work through 8139 times 504 step by step
8139 × 504 = 504 × (8139)
+ 504 × 9 yielding 4536
+ 504 × 30 yielding 15120
+ 504 × 100 yielding 50400
+ 504 × 8000 resulting in 4032000

= 4102056
