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13 is a prime number from 1-100. 13 is prime because it only has 2 factors, 1 and 13. It is said to be an unlucky number, because of some reasons. It is the sixth prime number, and the sixth prime number between 1 to 100.

## Proofs

• Therefore it has 2 factors.

## As an Exponent of Mersenne Number

213 - 1, which is the number 8,191, is a prime number. It is the 5th Mersenne Prime.

## ​Relationship with other odd numbers

### The numbers before

• The previous odd number, 11, is a prime number.
• There are no odd numbers between 11 and 13. As a result, they are twin primes.
• The odd number previous to 11 is 9. 9 is a square number.
• The odd number previous to 9 is 7. 7 is a prime number.
• 7 and 13 are six numbers apart; therefore, they are sexy primes.

### The numbers after

• The next odd number, 15, is not a prime number. It is divisible by 3 and 5.
• 17, the odd number following 15, is a prime number.
• 13 and 17 are four numbers apart; therefore, they are cousin primes.
• 19, the odd number following 17, is a prime number.
• 13 and 19 are six numbers apart; therefore, they are sexy primes.

## Trivia

• The fear of number 13 is called Triskaidekaphobia, which was founded at 1911.
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