Factors of 1
The factors of 1 are 1. 1 is neither prime nor composite.
Factors of 1
1
1 factor
Prime or Composite
Neither
Perfect Square
Yes
Prime Factorization
n/a
Sum of Factors
1 (0 without 1 itself)
Factor pairs of 1
Every factor has a partner that multiplies with it to give 1. Listing pairs from the outside in is the fastest way to find all the factors: once the two numbers in a pair meet in the middle (here at 1 × 1), you have them all.
| Pair | Check |
|---|---|
| 1 and 1 | 1 × 1 = 1 |
Divisibility checks for 1
The quick rules a student uses before dividing, applied to 1:
| Divisible by | Rule | For 1 | Result |
|---|---|---|---|
| 2 | last digit is even | last digit 1 | no |
| 3 | digit sum divisible by 3 | digits add to 1 | no |
| 4 | last two digits divisible by 4 | 1 ÷ 4 | no |
| 5 | last digit is 0 or 5 | last digit 1 | no |
| 6 | divisible by both 2 and 3 | odd, digit sum 1 | no |
| 8 | last three digits divisible by 8 | 1 ÷ 8 | no |
| 9 | digit sum divisible by 9 | digits add to 1 | no |
| 10 | last digit is 0 | last digit 1 | no |
Frequently Asked Questions
What are the factors of 1?
The factors of 1 are 1.
Is 1 a prime number?
1 is neither prime nor composite.
How many factors does 1 have?
1 has 1 factor.
Is 1 even or odd, and is it a perfect square?
1 is odd (2 is not a factor), and it is a perfect square: 1 × 1 = 1, which is why its factor list has an odd number of entries.
What is the sum of the factors of 1?
1 = 1. Leaving out 1 itself, the proper factors add to 0.
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