Supposedly they were nicknamed 'Bin Ladens' in some places, due to the association with money laundering. I have no idea how true that is.

Something we do actually know, though, is that Osama himself had two of them sewn into his clothing at the time of his death.

The €500 note was one of the world's most valuable banknotes. There's no denomination anywhere near it for, say, dollars or pounds or whatever.