3 is the second prime number, and the second single digit prime number. 3's prime factors are 1 and 3. It is said to be the first odd prime, because the previous prime number is 2, which is even.


  • It is divisible by 1: 3/1=3
  • It is not divisible by 2: 3/2=1.5
  • It is divisible by 3: 3/3=1
  • Therefore it has 2 factors, not 3, because 3 divided by 2 does not result in an integer value.

Relationship with other odd numbers

The numbers before

  • 2 is the first prime number. It is the only even prime number.
  • 1, the number before 2, is not a prime number.

The numbers after

  • The next odd number, 5, is a prime number.
    • There are no odd numbers between 3 and 5. As a result, they are twin primes.
  • 7, the odd number following 5, is a prime number.
    • 3 and 7 are four numbers apart, therefore, they are cousin primes.
  • 9, the odd number following 7, is not a prime number. It is a square number, and the first odd composite number.

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