Don't Factor the Factor!
AFM landing distance is 2500ft
2500ft x 1.67 = 4175ft
you can land on any runway greater than 4175ft and be legal for the 60% rule.
Multiply the AFM Landing Distance by these numbers depending on the conditions and operation to see the minimum runway length required.
1.25 80% if DAAP approved
1.43 80% + 15% for Wet Runway
1.67 60% Rule
1.92 60% Rule + 15% for Wet Runway