Is 16 a prime number?
16 is not a prime number. Here is a way to check it.
The answer
No. 16 is not a prime number: 2 × 8 = 16.
How to see that 16 is not prime
16 is even, and every even number can be divided by 2, so 2 is a factor as well as 1 and 16.
16 has 5 factors (1, 2, 4, 8 and 16), which make 3 factor pairs.
Split 16 into prime factors
Split off the smallest prime each time, and keep going until every part is prime:
- 16 = 2 × 8
- 16 = 2 × 2 × 4
- 16 = 2 × 2 × 2 × 2
With repeated primes written as powers, that is 2⁴. A small raised number tells you how many times to use that factor: for example, 2³ means 2 × 2 × 2.
16 in the times tables
16 turns up in 3 different times tables, the 2, 4 and 8: 2 × 8, 4 × 4 and 8 × 2.
Quick checks that catch 16
- The last digit, 6, is even, so 2 goes in.
- Half of it is 8, which is still even, so 4 goes in.
16 at a glance
Optional extra number facts:
- In words
- sixteen
- In Roman numerals
- XVI
- Odd or even
- Even: it ends in 6
- Square number
- 4 × 4 = 16
- Its factors add up to
- 31, or 15 without 16 itself. 16 is deficient: Deficient means this sum is less than the number.
The numbers either side of 16
- 15 is not prime. Its digits add up to 1 + 5 = 6, which is a multiple of 3. That means 15 is a multiple of 3 too, so 3 is a factor. Check 15 in full
- 17 is prime: 2 and 3 do not go into it, and 5 × 5 is already past 17. Check 17 in full
Turn the digits round
16 backwards is 61. 61 is prime: 2, 3, 5 and 7 do not go into it, and 11 × 11 is already past 61. Check 61 in full
Related pages
More numbers
Questions parents ask
Which prime numbers are either side of 16?
13 below it and 17 above it, a gap of 4.
What is 16 squared?
16 × 16 = 256.
What is the smallest number with as many factors as 16?
16 itself. No smaller number has 5 factors.
Continue your number practice
Explore the diagnostic for another set of practice questions.