Police, paramedics and an air ambulance were scrambled to the scene in Court Road in Chelsfield around 12.30pm on Saturday.
The cyclist was treated at the scene before being taken to a south London hospital in a critical condition.
The man later died in hospital, Scotland Yard confirmed on Wednesday afternoon.
"His family has been informed and is being supported by specialist officers," a Met spokesperson said.
The driver of the car - a grey Audi - stopped at the scene and is assisting police, the spokesperson added. There have been no arrests.
Detectives would like to speak with anyone who witnessed the collision, which happened close to Hewitts Farm, or captured it on dash cam.
Anyone with information is asked to contact the Serious Collision Investigation Unit on 020 8285 1574 or via 101 quoting reference CAD 3081/11Nov.
