- 18 Up on the Housetop
Factors of 18: 1, 2, 3, 6, 9, 18. Prime factorization: 18 = 2 x 3 x 3, which can also be written 18 = 2 x 3².
-For 26, the answer is: No, 26 is not a prime number
-28 = 1 x 28, 2 x 14, or 4 x 7. Factors of 28: 1, 2, 4, 7, 14, 28. Prime factorization: 28 = 2 x 2 x 7, which can also be written 28 = 2² x 7.