Number theory ( or arithmetic Especially in older sources ; see two following notes . ) is a branch of pure mathematics devoted primarily to the study of the integers , sometimes called '' The Queen of Mathematics '' because of its foundational place in the discipline .
Number theory ( or arithmetic Especially in older sources ; see two following notes . ) is a branch of pure mathematics devoted primarily to the study of the integers . 
 It is sometimes called '' The Queen of Mathematics '' because of its foundational place in the discipline .