Alright, let's work through 2104 times 3172 step by step
2104 × 3172 = 3172 × (2104)
+ 3172 × 4 yielding 12688
+ 3172 × 00 yielding 0
+ 3172 × 100 that equals 317200
+ 3172 × 2000 what gives us 6344000

= 6673888
