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All prime squares have exactly three factors.49 has exactly three factors: 1, 7, and 49.
There are three of them with exactly five factors.
A prime number has exactly two factors.
81 has 5 factors: 9x9 3 x 27 1 x 81
Squares of prime numbers have exactly three factors.
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All prime squares have exactly three factors.49 has exactly three factors: 1, 7, and 49.
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16 does.
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There are three of them with exactly five factors.
attitude, thinking and surroundings
Six has four factors and is in between the twin primes 5 and 7.
88 has exactly eight factors (1, 2, 4, 8, 11, 22, 44 & 88)
The numbers between 10 and 30 that have exactly 5 factors are 16 and 25. The number 16 has factors 1, 2, 4, 8, and 16. The number 25 has factors 1, 5, 25, but since it is a perfect square, it also includes the repeated factor of 5. These are the only two numbers between 10 and 30 that have exactly 5 factors.
In that range, only 100 has exactly 9 factors.
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