This feels wrong, at face value. Even in modern English, if I say I have a number of things, I almost certainly don't have just one. This does /not/ mean that one is not a number. It /does/ mean that the word "number" can have several uses.
I think it is fair to say that my statement is too strong to say it is wrong. My assertion would be that it is more complicated and almost certainly there is a lot lost in translation along the years.