1 and 5
16, 81, 256, 625 all have five factors.
1 and 5
Since 5 is a factor of 15, all of its factors are common.
The factors of 45 are: 1, 3, 5, 9, 15, 45.
81 has these five factors: 1 3 9 27 81.
The factors of 55 are 1, 5, 11, and 55. Prime factors of 55 are 5 and 11.
26, 36, 39, 52 and 78 are all factors of 468.
Multiply prime squares by themselves. 24, 34, 54 all have five factors.
All of the positive-integer factors of 16 are: 1, 2, 4, 8, and 16.
One and five
16 has five factors.
1, 3, 5, 15, 25, 75