I was playing in Freebitco.in during ~3 years, these are my achivements. The biggest numbers I rooled in Free BTC:
9993 - 1 time
9992 - 2 times
9990 - 1 time
9989 - 2 times

and never the bigger number than 9993. After reading this thread, now I am sure that Freebitco.in is cheating.

https://i.imgur.com/wl1LHXN.png