Alright, let's work through 6864 times 8145 step by step
6864 × 8145 = 8145 × (6864)
+ 8145 × 4 resulting in 32580
+ 8145 × 60 that results in 488700
+ 8145 × 800 resulting in 6516000
+ 8145 × 6000 that is equal 48870000

= 55907280
