The prime squares, like 4, 9, 25 and 49
Prime numbers have only two factors.
Prime numbers have exactly two factors. 53 and 59 are prime numbers.
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).
47
4, 9, 25 and 49 They are squares of prime numbers.
1,2,3,4,5,7,9,11,13,15,16,17,19,22,23,26,27,28,29,31,32,33,34,37,39,41,43,44,47,49
Because the prime numbers between 1and 50 only have exactly 2 unique factors.
6, 8, 10, 14, 15, 21, 22, 26, 27, 33, 34, 35, 38, 39, 46 have exactly four factors.
The prime numbers between 30 and 50 are 31, 37, 42, 43 and 47.
Using "^" for powers. I believe the smallest ODD number with exactly 5 factors would be 3^4 = 81. Since you say "at least", we could also consider numbers with 6 factors; the smallest of those would be 3^2 x 5 = 45. So that would be a number under 50.
It doesn't. 48 has the most factors of positive numbers under 50.
31 37 47