Is there any meaning or symbolism in the letter Q or the number 17 ? Definetly it isn't a biblical number (3,7,12,40,etc)

EDIT : I knew that it was because Q is the highest level of clearance. I wanted to know why the letter "Q" and not P, D, M, E,X, etc.

Is there any meaning or symbolism in the letter Q or the number 17 ? Definetly it isn't a biblical number (3,7,12,40,etc)