A number has exactly three factors if and only if it is the square of a Prime number.
Squares of prime numbers have exactly three factors.
By definition, a prime number has exactly two factors. So, there are no prime numbers with exactly three factors.
Prime squares
The squares of all prime numbers have exactly 3 factors. The numbers under fifty that are the squares of primes are 4 (1, 2, and 4), 9 (1, 3, and 9), 25 (1, 5, and 25), and 49 ( 1, 7, and 49).
Prime numbers have exactly two factors.All prime numbers have only 2 factors whereas composite numbers have more than 2 factors
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
2 and 3
3, 5 and 7
4 and 9
Prime squares have three factors. 4, 9, 25
2 4 6
Squares of prime numbers, like 4, 9 and 25.