Americans need 1.26m to retire?

This ($1,260,000) is often cited as the amount Americans need to retire.

Down from 1.46m last year, so is this saying at a certain age or any age?

There is a difference in retiring at 42 year old with 1.26m and retiring at 62 with 1.26m.

I am considering retiring age 55 with 1.7m, but the fact i am still 7 years from minimum ss and 10 years from medicare is concerning to me.

Does anyone familiar with yhe study know what age the article is referring to?