Is 56 a prime number?
56 is not a prime number. Here is a way to check it.
The answer
No. 56 is not a prime number: 2 × 28 = 56.
How to see that 56 is not prime
56 is even, and every even number can be divided by 2, so 2 is a factor as well as 1 and 56.
56 has 8 factors (1, 2, 4, 7, 8, 14, 28 and 56), which make 4 factor pairs.
Split 56 into prime factors
Split off the smallest prime each time, and keep going until every part is prime:
- 56 = 2 × 28
- 56 = 2 × 2 × 14
- 56 = 2 × 2 × 2 × 7
With repeated primes written as powers, that is 2³ × 7. A small raised number tells you how many times to use that factor: for example, 2³ means 2 × 2 × 2.
56 in the times tables
56 turns up in 2 different times tables, the 7 and 8: 7 × 8 and 8 × 7.
Quick checks that catch 56
- The last digit, 6, is even, so 2 goes in.
- Half of it is 28, which is still even, so 4 goes in.
56 at a glance
Optional extra number facts:
- In words
- fifty-six
- In Roman numerals
- LVI
- Odd or even
- Even: it ends in 6
- Its factors add up to
- 120, or 64 without 56 itself. 56 is abundant: Abundant means this sum is greater than the number.
The numbers either side of 56
- 55 is not prime. 55 ends in 5, and every number ending in 5 or 0 is in the 5 times table, so 5 is a factor. Check 55 in full
- 57 is not prime. Its digits add up to 5 + 7 = 12, which is a multiple of 3. That means 57 is a multiple of 3 too, so 3 is a factor. Check 57 in full
Turn the digits round
56 backwards is 65. 65 is not prime. 65 ends in 5, and every number ending in 5 or 0 is in the 5 times table, so 5 is a factor. Check 65 in full
Related pages
More numbers
Questions parents ask
Which prime numbers are either side of 56?
53 below it and 59 above it, a gap of 6.
What is 56 squared?
56 × 56 = 3136.
What is the smallest number with as many factors as 56?
24. It has 8 factors, the same as 56.
Continue your number practice
Explore the diagnostic for another set of practice questions.