I had a 6 digit one, then lost it, then got 49053668. I've forgotten many passwords but never this. I actually could login to the web app, using the oldest password I used that I can remember, but it doesn't show any old contacts except one. Oh well. So long and thanks for all the <s>fish!</s> great moments!

edit: Found a video of an old client working: https://www.youtube.com/watch?v=I_pYWRfeYKs