As people have said above, the numbers are not recycled, but the numbers are given in some sort of order, I would guess sequentially within a state, or maybe county? Not sure how it is broken down? The beginning numbers give away what state you were in when it was issued. Mine starts with a 122 which seems to be NY or parts of NY. Lots of people around me here in TN start with 4 so I guess that signifies this state. Since you are curious about the numbers, you might want to research how the numbers are given, the logic behind it, what numbers were given during what years etc. Unfortunately SS security numbers are seen as something that needs to be protected for identity theft reasons, or maybe we could find out who got their number immediately before and after ourselves.
Most things like this have some sort of interesting system. Even things like our roads, more specifically interstates have a logical system. All off interstates run north south, evens run east west. Odds go lowest to highest east to west, so you can know that I75 is west of I95, and I80 is north of I40. These type of number systems and how work always interest me.