ch7 ex2

#7.2.1
def factors(num):
    listfactors=[]
    for i in range(1, num+1):
        if num%i==0:
            listfactors.append(i)
    return listfactors

#7.2.2
def prime(n):
    if len(factors(n))==2:
        return True
    else:
        return False

#7.2.3
def perfect_number(n):
    sum=0
    for i in factors(n):
        sum+=i
    sum=sum-n

    if sum==n:
        return True
    else:
        return False
print(perfect_number(6))