Divisor  Definition with Examples
A divisor is represented in a division equation as:
Dividend ÷ Divisor = Quotient. 
On dividing 20 by 4 , we get 5. Here 4 is the number that divides 20 completely into 5 parts and is known as the divisor. Its division equation is
Similarly, if we divide 20 by 5, we get 4. Thus, both 4 and 5 are divisors of 20.
The divisor is any number that divides another number. A factor, however, is a divisor that divides the number entirely and leaves no remainder.
In the example above, 4 and 5 are the factors of 20.
Let's consider another example,
The factors and divisors of 15 are: 1, 3, 5, 15
To find the factors of a number, say 12, we follow the given steps:
1. Start with 1, and write multiplication facts such that the product is 12 such as 1 × 12.
2. Continue the same way to find other multiplication facts till we reach a pair of nearest factors or divisors as given:
1 ×12 , 2×6, 3×4
3. Write down all the numbers in the multiplication fact as these are the divisors of 12.
4. So, the divisors or factors of the number 12 are 1,2,3,4,6 and 12.
There are different styles of expressing a division equation. In the images below, the various methods of writing a divisor are shown below:
Special cases
1. The number 1 is the divisor of all the numbers.
Reason: When the divisor is 1, then the quotient is the same as the dividend.
Look at the given examples,
34 1 = 34
15 1 = 15
2. The number itself is always one of the divisors of the number.
Reason: When the divisor is the same as the dividend, then the answer to such a division is always 1.
Look at the given examples,
34 34 = 1
15 15 = 1
3. When the divisor is a smaller number than the dividend, then the answer is not a whole number but a decimal number.
For example,
Fun Facts

When we divide two numbers, the number that is being divided is the dividend, whereas the number by which we divide is the divisor. For example, 12 candies are to be divided among 3 children. So we have 12 ÷ 3. Here, 12 is the dividend, and 3 is the divisor.
A divisor is any number that divides another number. A factor, however, is a divisor that divides the number entirely and leaves no remainder.
Yes, all numbers are divisors of themselves. This is because every number divides itself and gives 1 as the quotient. For example, if we have 12 ÷ 12, then 12 becomes the divisor of 12, and 1 becomes the quotient.
If the remainder is 0, then Divisor = Dividend ÷ Quotient. If the remainder is not 0, then Divisor = (Dividend  Remainder) /Quotient.