They are: 41, 43 and 47 that have only 2 factors because they are all prime numbers
The numbers for which the sum of its proper factors is 1 less than the number is the powers of 2; less than 50 these are: 2, 4, 8, 16 & 32.
100
4,27,and38
Every prime number has exactly two factors. They are '1' and the number itself. There are 15 prime numbers less than 50. A few of them are 2, 3, 5, 7, 11, 13, and 47.
positive square numbers less than 50 are 7 these are : 1,4,9,16,25,36,49.These are less than 50.
4, 9, 25 and 49 They are squares of prime numbers.
49, 25
The numbers for which the sum of its proper factors is 1 less than the number is the powers of 2; less than 50 these are: 2, 4, 8, 16 & 32.
4,27,and38
Every prime number has exactly two factors. They are '1' and the number itself. There are 15 prime numbers less than 50. A few of them are 2, 3, 5, 7, 11, 13, and 47.
There are 15 prime numbers less than 50
100
positive square numbers less than 50 are 7 these are : 1,4,9,16,25,36,49.These are less than 50.
4, 9, 25, 49
4, 9, 25 and 49 They are squares of prime numbers.
Nothing special. They are squares of prime numbers.
A number is prime if its only two factors are one and itself.