Seven

The seven (7) is the natural number that follows 6 and precedes 8.

A number seven made with neon lights.

Math

• It's the fourth prime number after 5 and before 11.
• The polygon of 7 sides receives the name of heptágone.
• 2.o prime number of Mersenne (2 ³ - 1), it is not only a cousin of Mersenne but it is also a double cousin of Mersenne since the exponent 3, it is in itself a cousin of Mersenne.
• Its minimal primitive root is 3, since 2³ ≡ 1 mod(7)
• 7! = 5040, which can well express the number of successive modes of appearance of seven different plagues.
• The first 7 rational prime numbers are: 35, 7, 11, 13, 17, 19
• Woodall's prime number.
• The problems of the millennium are seven mathematical problems that were declared by the Clay Mathematics Institute in 2000. Currently, six of the problems remain unresolved.
• It is a term of the succession of Padovan.
• It forms a triplet of sexy prime numbers (7,13,19).
• He can't make a difference to two cousins.
• 3.♪ term of the succession of Sylvester.
• 1.♪ Newman-Shanks-Williams' prime number.
• 2nd prime lucky number.
• 1.♪ Happy cousin number.
• Seven is the smallest natural number that cannot be represented as the sum of the three integer squares. (See the Theorem of the four squares.
• 7 is the only number D for which equation 2 ⁿ - D = x ² has more than two solutions for n and x natural. In particular, equation 2 ⁿ - 7 = x ² is known as the Ramanujan-Nagell equation.
• 99.999 divided by 7 is exactly 142.857.
• There are seven elementary types of catastrophes. See catastrophe theory.
• It's a self-number.

Chemistry

• Nitrogen atomic number (N).

Astronomy

• Messier M7 object is an open cluster in the constellation of Scorpio.
• NGC 7 is a spiral galaxy located in the constellation of the sculptor.
• Uranus Planet

Biology

• Almost all mammals have seven cervical vertebrae
• There are 7 types of viruses, according to Baltimore classification
• There are 7 types of feces, according to the Bristol feces scale

Popularity

• The origin of this popularity is in the observation of heaven by the ancient astronomers. The vast majority of the stars did not change the position of each other during the year. However, they observed seven celestial bodies that did. The Sun and the Moon, the first two, were obviously part of them. The other five were the planets that can be seen in plain sight, Mercury, Venus, Mars, Jupiter and Saturn, and that ancient peoples considered mobile stars.^{[chuckles]required]}
• These seven stars (baptized in honor of Roman gods) gave to the days of the week their names in many languages: Monday (Luna), Tuesday (Mars), Wednesday (Mercurio), Thursday (Jupiter, Jove) and Friday (Venus). In Spanish, "Satur" came from the name the Hebrew feast "Sabbat" and "domingo" of the Latin word "Dominus" "the Lord" (The Lord)domin invasioncus [dies][day] of the Lord. However, in languages such as English, the original names of these two days are kept: Saturday of Saturn (Saturno) and Sunday of «Sun» 'the Sun'.

Diversity of issues

• The seven days of the week: Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday.
• The seven hills of Rome
• The seven notes of the scale plus musical notes: do, re, mi, fa, sol, la, si.
• The sum of the points on the opposite faces of the 6-sided dice, adds 7.
• The seven deadly sins: pride, greed, lust, anger, gull, envy and laziness.
• The seven seas, an expression that is used in speaking, in general, of all the seas or of a certain group of seas that varies according to the time and the peoples.
• The seven metals, an expression used when referring to known metals in Antiquity (gold, copper, silver, lead, tin, iron and mercury).

• The seven arms of Menorah, the Jewish sacred and liturgical lampstand.

• The Seven Wise of Greece.
• The seven sacraments: Baptism, confirmation, Eucharist, penance, anointing of the sick, marriage and priestly order.
• The seven wonders of the ancient world.
• The seven samurai
• Seven years in Tibet
• The seven magnificent
• Bushidō's "seven virtues"
• The seven Catholic gifts of the Holy Spirit: Wisdom, intelligence, counsel, strength, science, mercy and fear of God.
• The seven games of Alfonso X el Sabio.
• The 7 archangels.
• The seven fine arts: Architecture, dance, sculpture, music, painting, literature and cinematography.
• The seven caves from where the 7 Chichimecas villages come from.
• The seven heavens of Islam.
• The seven Greek modes.
• Seven heads of the beast of the Book of Revelations.
• Seven laps of the Israelites around Jericho on the seventh day outside their walls.
• The seven children of Écija.
• The seven Lara infants.
• Ana and the seven
• In Poniente (from Ice Song and Fire and Game of Thrones) there are 7 kingdoms: Northern Kingdom, Kingdom of the Islands and the Rivers, Kingdom of the Mountain and the Valley, Kingdom of the Rock, Kingdom of the Dominion, Kingdom of the Storm and the Principality of Dorne.
• In the west (from the Song of Ice and Fire and Game of Thrones) the faith of the 7, where there are 7 gods that are one. And the expressions: "for the seven" or "seven hells"
• The 7 Horrocruxes of Lord Voldemort in Harry Potter.
• The 7 Dragon spheres in the Dragon Ball universe.
• The 7 Divine Dante Hell comedy.
• The seven plagues that appeared to soften the heart of Pharaoh
• The Seven Wise of the Bamboo Forest ^{[chuckles]required]}
• Seven sages (The Legend of Zelda).
• The Seven Arcants (Genshin Impact)
• The 7 Principles of the Universe (Kybalion)
• The Seven Snow White Enanites
• The 7 E-Guardias (Gamesa)