Is 12 a prime number?
12 is not a prime number. Here is the quickest way to see it.
The answer
No. 12 is not a prime number: 2 × 6 = 12.
How to see that 12 is not prime
12 is even, and every even number can be divided by 2, so 2 is a factor as well as 1 and 12.
12 has 6 factors (1, 2, 3, 4, 6 and 12), which make 3 factor pairs.
Split 12 into prime factors
Split off the smallest prime each time, and keep going until every part is prime:
- 12 = 2 × 6
- 12 = 2 × 2 × 3
With the repeated primes written as powers, that is 2² × 3.
12 in the times tables
12 turns up in 5 different times tables, the 2, 3, 4, 6 and 12: 2 × 6, 3 × 4, 4 × 3, 6 × 2 and 12 × 1.
Quick checks that catch 12
- The last digit, 2, is even, so 2 goes in.
- The digits add up to 3, which is in the 3 times table, so 3 goes in.
- Half of it is 6, which is still even, so 4 goes in.
- It is even and passes the check for 3 as well, so 6 goes in.
12 at a glance
- In words
- twelve
- In Roman numerals
- XII
- Odd or even
- Even: it ends in 2
- Its factors add up to
- 28, or 16 without 12 itself, which makes 12 an abundant number
The numbers either side of 12
- 11 is prime: 2 and 3 do not go into it, and 5 × 5 is already past 11. Check 11 in full
- 13 is prime: 2 and 3 do not go into it, and 5 × 5 is already past 13. Check 13 in full
Turn the digits round
12 backwards is 21. 21 is not prime. Its digits add up to 2 + 1 = 3, which is a multiple of 3. That means 21 is a multiple of 3 too, so 3 is a factor. Check 21 in full
Related pages
More numbers
Questions parents ask
Which prime numbers are either side of 12?
11 below it and 13 above it, a gap of 2.
What is 12 squared?
12 × 12 = 144.
What is the smallest number with as many factors as 12?
12 itself. No smaller number has 6 factors.
Number facts are the base of 11+ maths
Factors, multiples, primes and square numbers come up all over 11+ maths, from simplifying fractions to ratio. The free diagnostic checks maths, English and both kinds of reasoning, and shows what to practise next. No card is required.