Simplify the following text for a Grade 7 native English-speaking person.
Original: In number theory , the totient of a positive integer is the number of integers less than the number which are coprime to n ( they share no factors ) .
Simplified: In number theory , the totient of a positive integer n is defined to be the number of positive integers less than or equal to n that are coprime to n ( i.e. having no common positive factors other than 1 ) .