Is $6 million dollars enough to retire on at age 36 when pulling in only $300,000 to $500,000 a year?

I have a friend in tech who is able to save up almost $300,000 to $500,000 a year, so I told them maybe they can retire at the age of 36. They said 6 million dollars might not be enough for a retirement in a major city. So I wanna ask some of the folks in here if this is enough to retire on?