I'm studying for the SAT on collegeboard.org, and I came across the problem: `What is the least positive integer that has the same number of positive factors as 175?`

The answer was `12`, explained as:

`The number 175 is equal to 5 x 7 x 5. It has a total of 6 positive factors: 1, 5, 7, 25, 35, and 175. The numbers with 6 positive factors are of the form`$p\_1^2\*p\_2$`or`$p^5$`. The least number of the first form is 12. The least number of the second form is 32. Thus, the answer is 12, which has the positive factors 1, 2, 3, 4, 6, and 12.`

I've never learned anything about the number of factors for a number, so this line: `The numbers with 6 positive factors are of the form`$p\_1^2\*p\_2$`or`$p^5$ doesn't make sense to me. Out of context, I understand that $p\_1$ is 2, but I don't understand where those two formulas came from or what p is supposed to be the set of.