I paid social security for about a year in 2004, and I haven't paid it since. Can I make it up now? how much is it? Especially old-age insurance?

I want to know what you mean: do you want to pay social security again? Social security from 2005 to now still needs to be paid back. If you pay it back, you won't pay it back, and there are many late fees. If you want to pay social security, start paying it this year. If you are old, how many years will it take to reach retirement age? You can ask me again.