Thirteen

Thirteen (13 in decimal number system) is the juxtaposition of 1 and 3.

Math

• 6.o prime number, after eleven and before seventeen.
• It is a permutable cousin with 31 (since when changing the position of numbers you get another prime number).
• 13 is the sum of two cousins. 13 = 2 + 11.
• 13 = 3+3+7 = 5+5+3 odd as a sum of three cousins
• The 13 is the eighth term of the Fibonacci succession, after eight and before twenty-one.
• Its summation is 91, which is 13 x 7 or 13 weeks, duration of a station.
• In a succession of 13 elements, the central term is 7, or, if subindized, starting with 1. However, by subindizing from 0, the central term is the term 6.o.
• If we consider the succession of the first five prime numbers 2, 3, 5, 7 and 11. 13 is the sum of extremes 11 and 2, and sum of intermediates 3, 5 and 7 minus the first 2.
• 13 is a pioneering number. 13 = 22{displaystyle scriptstyle 2^{2}} + 32{displaystyle scriptstyle 3^{2}}. In addition, it divides to the sum of two 82+12 squares.
• 13 measures the hypotenuse of a rectangle triangle of kennels 5 and 12
• Form a pair of sexy prime numbers along with 19.
• There are 13 solids of Archimedes.
• It is part of the Pythagorean (5, 12, 13).
• A standard bull can be cut into 13 pieces with only 3 flat cuts.

Science

• Atom number of aluminium.
• The Messier 13 Object is the Hercules Cluster (also known as the Great Hercules Cluster, Messier 13, M13 or NGC 6205 and informally as the Great Cluster).

Religion

Catholicism

• The apparitions of the Virgin of Fatima in 1917 were declared to occur on the 13th of six consecutive months.
• In Catholic devotional practice, the number thirteen is also associated with St. Anthony of Padua, as his party falls on June 13. A traditional devotion called Thirteenth Tuesday of San Antonio implies praying for the saint every Tuesday for a period of thirteen weeks.

Judaism

• In Judaism, 13 means the age at which a mature child becomes a Bar Mitzvah, that is, a full-fledged member of the Jewish faith (it counts as a member of Minyan).
• The number of the principles of the Jewish faith according to Maimonides.
• According to the Rabbinic commentary on Torah, God has 13 attributes of Mercy.
• The number of circles or "nodes", which make up the Cube of Metatron in the Kabbalistic teachings.

Zoroastrianism

The number 13 had been considered sinister and evil in the ancient Persian civilization and Zoroastrianism. Since the beginning of the Nourooz tradition, the 13th day of every Iranian new year is called Sizdah Sea-dar, and this tradition lives on among Iranians, both within Iran and abroad. It is considered a day when the power of evil could cause difficulties for people. Therefore, people leave the urban areas for a day and camp in the countryside.

Islamic

In Shia Islam 13 means the 13th day of the month of Rajab (lunar calendar), which is the birth of Imam Ali. 13 is also a total of 1 Prophet and 12 Imams in the Shia school of thought.

Mayan culture

In the Mayan cultures, 13 belonged to the sacred numbers, since their calendars were based on the 13 moons of the year.

Superstition about the number 13

The triskaidekaphobia (from the Greek τρεισκαιδέκα, treiskaideka, 'thirteen', derived from τρεῖς, treîs, 'three'; καὶ, kai, 'and'; δέκα, deka, 'ten'; together with φοβία, phobia, from φόβος, phobos, 'fear') is the irrational fear of the number 13. It is normally considered a superstition. The specific phobia of Friday the 13th is called friggatriscaidecaphobia (from the Viking goddess Frigg from which the word Friday comes).

Some Christian communities consider it a good luck number. Some Catholic celebrations are celebrated on the 13th.