Alright, let's work through 2409 times 9921 step by step
2409 × 9921 = 9921 × (2409)
+ 9921 × 9 what gives us 89289
+ 9921 × 00 resulting in 0
+ 9921 × 400 resulting in 3968400
+ 9921 × 2000 resulting in 19842000

= 23899689
