4, 9, 25 and 49.
3, 5 and 7
Prime numbers have exactly two factors. 3 has exactly two factors: 1 and 3. So 3 is prime. Composite numbers have more than two factors. 4 is composite because it has three factors: 1, 2, and 4.
Squares of prime numbers, like 4, 9 and 25.
Yes. Composite numbers have more than exactly two factors; 39 has four factors: 1, 3, 13, 39. Prime numbers have exactly two factors, eg 3 has the two factors 1 and 3. Square numbers have an odd number of factors, eg 36 has nine factors: 1, 2, 3, 4, 6, 9, 12, 18, 36. The number 1 is not prime as it only has one factor: 1.
there are 3 no.2,3 & 5
All numbers that are the square of primes have exactly 3 factors.
Squares of prime numbers have exactly three factors.
Numbers with exactly three factors are squares of prime numbers.
The squares of all prime numbers above 2 have exactly 3 factors.
By definition, a prime number has exactly two factors. So, there are no prime numbers with exactly three factors.
Prime squares
A number has exactly three factors if and only if it is the square of a prime number.
2 and 3
3, 5 and 7
Prime numbers have exactly two factors. 3 has exactly two factors: 1 and 3. So 3 is prime. Composite numbers have more than two factors. 4 is composite because it has three factors: 1, 2, and 4.
4 and 9
Prime squares have three factors. 4, 9, 25