What is 1 3?

13 (thirteen) is the natural number following 12 and preceding 14.

• Mathematics: In <a href="https://www.wikiwhat.page/kavramlar/Mathematics">Mathematics</a>, 13 is the 6th prime number, a <a href="https://www.wikiwhat.page/kavramlar/Mersenne%20prime%20exponent">Mersenne prime exponent</a> (2¹³-1 = 8191, which is a Mersenne prime), and a <a href="https://www.wikiwhat.page/kavramlar/Fibonacci%20number">Fibonacci number</a>.

• Cultural Significance: In many Western cultures, 13 is considered an unlucky number, leading to superstitions like <a href="https://www.wikiwhat.page/kavramlar/Friggatriskaidekaphobia">Friggatriskaidekaphobia</a> (fear of Friday the 13th) and Triskaidekaphobia (fear of the number 13). Some buildings skip the 13th floor, labeling it 14 or 12A.

• Science: In <a href="https://www.wikiwhat.page/kavramlar/Chemistry">Chemistry</a>, 13 is the atomic number of aluminum.

• Other: 13 is the number of stripes on the American flag, representing the original thirteen colonies.