Alright, let's work through 2129 times 4004 step by step
2129 × 4004 = 4004 × (2129)
+ 4004 × 9 giving us 36036
+ 4004 × 20 yielding 80080
+ 4004 × 100 which equals 400400
+ 4004 × 2000 yielding 8008000

= 8524516
