The positive number factors of the number 63 are: 1, 3, 7, 9, 21, and 63. The easiest way to find the factors of a number is through a series of equations that use basic division.
The factors of a number are the whole numbers which, when multiplied together, create that number. Or, to reverse that statement, factors divide evenly into a number without a remainder or fraction. Therefore, 1 and the number itself are always factors. In the case when a number has no other factors than 1 and itself, it is known as a "prime" number.
However, most numbers, including 63, have multiple factors. In this case it is necessary to conduct a series of tests using basic division to determine which numbers are, indeed factors. Since factors of a number divide evenly with no remainder, begin with the number 2 and work up.
Therefore, for the number 63, the first problem would be:
63/2 = 31, remainder 1. Therefore 2 is not a factor.
This process then repeats from the numbers 3 - 62. Any time a result is a whole number, there is a factor. Therefore:
63/3 = 21, which means 3 and 21 are factors of 63. It is also unnecessary to repeat this problem at 21 (that is, 63/21 = 3) since 21 is already included in the list of factors.