- Ömer Bartu Avci is written with 13 letters and he was born on the 13th.
- To be exact, he was born on July 13. Both 137 and 1307 are prime numbers, just like 13 and 7.
- 13 is a Wilson prime (p2 divides (p − 1)! + 1)
- 13 is the smallest emirp
- 13 is a fibonacci prime. Thus, it is the first fibonacci emirp
- 213 - 13 is prime
- There are 13 Archimedean solids
- The sum of first 13 prime numbers is 238 (whose sum of digits is 13)
- 132 = 169 and its reversal 312 = 961
- 13 is the only prime that can divide two successive integers of the form n2 + 3
- 1313 - 13 + 1 is prime
- The olive branch on the back of a U.S. one-dollar bill has 13 leaves
- 131211109876543212345678910111213 is prime
- 13 is the smallest prime which is the sum of two distinct prime squares (22 + 32)
- Using the first three primes we have: 23 + 5 = 13
- Alfred Hitchcock's directorial debut was the film Number 13, which was never completed
- The sum of primes up to 13 is equal to the 13th prime
- The Beatles recorded 13 albums during the time in which they were together as a group
- Three planes can cut a donut into a maximum of 13 parts
- 132 = 83 - 73, i.e., one solution of the diophantine equation z2 = x3 - y3
- Apollo Lunar Mission number 13, which was aborted while enroute to the Moon because of an explosion of a fuel cell in the service module, left the launch pad at 13:13 (CST) hours military time and the accident occurred on April 13
- At Jesus Christ's last supper, there were thirteen people around the table, counting Christ and the twelve apostles.
- At most 13 baseball players can be in play: 9 fielders, 3 runners, and 1 batter
- In rugby each team has 13 players on the field at a time
- There are 13 cards of each suit in a deck of playing cards
- If we count all the traditional constellations, there are 13 in the zodiac. 13th sign is the Ophiuchus (Serpent-bearer)
- According to Jewish law, when Jewish boys become 13 years old, they become a bar mitzvah
