You just divide it by 21 and if there is no remainder then it went in evenly.
3
Because 3 divides evenly into 21 and 36 with no remainder.
441 divides evenly by these numbers: 1 3 7 9 21 49 63 147 and 441.
A factor divides evenly into a given number.
Because 21 is the largest number that divides evenly into both of those numbers with no remainder.
A number that divides evenly into another number is called a factor.
A factor divides evenly into a given number.
1 is the smallest number that divides any positive integer evenly.
A number that divides into a whole number evenly is called a "factor" of that number.
You can determine if a binomial divides evenly into a polynomial by using the remainder theorem or synthetic division. If the remainder is 0, then the binomial divides evenly into the polynomial.
The smallest prime number that divides 98 evenly is 2.