Here are some math facts about the number 28: The number 28 is the fourteenth even number as is a multiple of 2.The number 28 has six distinct factors. These are 1. 2. 4. 7. 14 and 28.It is also recognised as a perfect number as if you sum up all the factors (excluding 28) you get a total of 28 (12471428).The prime factor decomposition of 28 is 2 x 2 x 7. The square of 28 is 784. Also if you square root 28 you get 5.29 rounded to 3 significant figures. 28 as a decimal is 0.28 and as fraction is 725.The cube of twenty eight is 21952.