Is 93 a prime number?
93 is not a prime number. Here is the quickest way to see it.
The answer
No. 93 is not a prime number: 3 × 31 = 93.
How to see that 93 is not prime
Its digits add up to 9 + 3 = 12, which is a multiple of 3. That means 93 is a multiple of 3 too, so 3 is a factor.
93 has four factors: 1 and 93, plus one pair in between, 3 and 31.
Split 93 into prime factors
93 splits straight into two primes, 3 × 31, so its factor tree has only one branch.
93 in the times tables
No fact from the 2 to 12 times tables, up to × 12, makes 93. Its smallest pair, 3 × 31, needs the 31 times table, which goes past 12.
Quick checks that catch 93
- The digits add up to 12, which is in the 3 times table, so 3 goes in.
93 at a glance
- In words
- ninety-three
- In Roman numerals
- XCIII
- Odd or even
- Odd: it ends in 3
- Its factors add up to
- 128, or 35 without 93 itself, which makes 93 a deficient number
The numbers either side of 93
- 92 is not prime. 92 is even, and every even number can be divided by 2, so 2 is a factor as well as 1 and 92. Check 92 in full
- 94 is not prime. 94 is even, and every even number can be divided by 2, so 2 is a factor as well as 1 and 94. Check 94 in full
Turn the digits round
93 backwards is 39. 39 is not prime. Its digits add up to 3 + 9 = 12, which is a multiple of 3. That means 39 is a multiple of 3 too, so 3 is a factor. Check 39 in full
Related pages
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Questions parents ask
Which prime numbers are either side of 93?
89 below it and 97 above it, a gap of 8.
What is 93 squared?
93 × 93 = 8649.
What is the smallest number with as many factors as 93?
6. It has 4 factors, the same as 93.
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.