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.
- Therefore it has 2 factors.
As an Exponent of Mersenne Number
23 - 1, which is the number 7, is a prime number. It is the 2nd Mersenne Prime.
Relationship with other 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 number, 4, is the first composite number, and a square number. It is the square of 2.
- The next odd number, 5, is a prime number.
- There are no odd numbers between 3 and 5, and they are two numbers apart. 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.
- Trilogy refers to a set of three works of art that are connected, either as a single work or three individual works.
- Lithium's atomic number and number of electrons are 3.
- Tritium / hydrogen-3, has a nucleon number of 3.
- In basketball, a shot behind the three-point arc is worth three points, unless in the 3x3 variant.
- In baseball, 3 strikes are required for the player to be considered "out", and 3 outs are required for the attacking team to exchange with the opposing team.
- In The Legend of Zelda series, there is a sacred relic called Triforce, which consists of three separate golden triangles.