Alright, let's work through 3991 times 8617 step by step
3991 × 8617 = 8617 × (3991)
+ 8617 × 1 producing 8617
+ 8617 × 90 resulting in 775530
+ 8617 × 900 which equals 7755300
+ 8617 × 3000 producing 25851000

= 34390447
