If Falcon 9's are used for the launches this would be 1440 Starlink satellites. There are four launches planned in 2019. There would be a total of 1680 Starlink satellites if all of them worked and they were launched 60 at a time.
SpaceX's Starlink launch cadence will likely average "two a month," in addition to customer launches, Gwynne Shotwell, SpaceX's president and chief operating officer, said at the World Satellite Business Week conference here.
Shotwell estimated SpaceX will do seven to eight more missions this year, including Starlink. SpaceX has flown 10 rockets this year — eight Falcon 9s and two Falcon Heavies. Shotwell didn't say how many total launches SpaceX plans in 2020, only that it is "much higher" than this year's projected max of 18.