Python
# Program to check perfect number
num = int(input("Enter a positive integer: "))
if num <= 0:
print("Number must be positive.")
else:
total = 0
for i in range(1, num):
if num % i == 0:
total += i
if total == num:
print(num, "is a perfect number")
else:
print(num, "is not a perfect number")Output
Enter a positive integer: 6 6 is a perfect number
A perfect number equals the sum of its positive divisors excluding itself. We loop from 1 to num-1 and sum divisors to compare with num.