Is 48 a prime number?
48 is not a prime number. Here is the quickest way to see it.
The answer
No. 48 is not a prime number: 2 × 24 = 48.
How to see that 48 is not prime
48 is even, and every even number can be divided by 2, so 2 is a factor as well as 1 and 48.
48 has 10 factors (1, 2, 3, 4, 6, 8, 12, 16, 24 and 48), which make 5 factor pairs.
Split 48 into prime factors
Split off the smallest prime each time, and keep going until every part is prime:
- 48 = 2 × 24
- 48 = 2 × 2 × 12
- 48 = 2 × 2 × 2 × 6
- 48 = 2 × 2 × 2 × 2 × 3
With the repeated primes written as powers, that is 2⁴ × 3.
48 in the times tables
48 turns up in 4 different times tables, the 4, 6, 8 and 12: 4 × 12, 6 × 8, 8 × 6 and 12 × 4.
Quick checks that catch 48
- The last digit, 8, is even, so 2 goes in.
- The digits add up to 12, which is in the 3 times table, so 3 goes in.
- Half of it is 24, which is still even, so 4 goes in.
- It is even and passes the check for 3 as well, so 6 goes in.
48 at a glance
- In words
- forty-eight
- In Roman numerals
- XLVIII
- Odd or even
- Even: it ends in 8
- Its factors add up to
- 124, or 76 without 48 itself, which makes 48 an abundant number
The numbers either side of 48
- 47 is prime: 2, 3 and 5 do not go into it, and 7 × 7 is already past 47. Check 47 in full
- 49 is not prime. 49 is odd, its digits do not add up to a multiple of 3, and it does not end in 5, so the quick checks for 2, 3 and 5 all fail. Try 7 next: 7 × 7 = 49. Check 49 in full
Turn the digits round
48 backwards is 84. 84 is not prime. 84 is even, and every even number can be divided by 2, so 2 is a factor as well as 1 and 84. Check 84 in full
Related pages
More numbers
Questions parents ask
Which prime numbers are either side of 48?
47 below it and 53 above it, a gap of 6.
What is 48 squared?
48 × 48 = 2304.
What is the smallest number with as many factors as 48?
48 itself. No smaller number has 10 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.