No problem, we've got 8644 and 9640 to multiply
8644 × 9640 = 9640 × (8644)
+ 9640 × 4 giving us 38560
+ 9640 × 40 that results in 385600
+ 9640 × 600 that equals 5784000
+ 9640 × 8000 what gives us 77120000

= 83328160
