<P> A positive divisor of n (\ displaystyle n) which is different from n (\ displaystyle n) is called a proper divisor or an aliquot part of n (\ displaystyle n). A number that does not evenly divide n (\ displaystyle n) but leaves a remainder is called an aliquant part of n (\ displaystyle n). </P> <P> An integer n> 1 (\ displaystyle n> 1) whose only proper divisor is 1 is called a prime number . Equivalently, a prime number is a positive integer which has exactly two positive factors: 1 and itself . </P> <P> Any positive divisor of n (\ displaystyle n) is a product of prime divisors of n (\ displaystyle n) raised to some power . This is a consequence of the fundamental theorem of arithmetic . </P> <P> A number n (\ displaystyle n) is said to be perfect if it equals the sum of its proper divisors, deficient if the sum of its proper divisors is less than n (\ displaystyle n), and abundant if this sum exceeds n (\ displaystyle n). </P>

When is a number called a divisor of a number