Typically Mach .79 - .81, initial cruise level depending on direction of travel fl400 for 500 mile, fl380 for 2500, and fl360 for 5000 mile. Cost index in low teens.
In practice Mach .83 would probably be about as fast as you'd want to go for comfort, with .81 a more typical figure. The aircraft is never flown at Mach numbers in excess of .84.
Hope this helps