19 (number)

← 18 20 → 19
← 10 11 12 13 14 15 16 17 18 19 → List of numbers — Integers 0 10 20 30 40 50 60 70 80 90 →
Cardinal	nineteen
Ordinal	19th (nineteenth)
Numeral system	nonadecimal
Factorization	prime
Divisors	1, 19
Roman numeral	XIX
Binary	100112
Octal	238
Duodecimal	1712
Hexadecimal	1316

19 (nineteen) is the natural number following 18 and preceding 20. It is a prime number.

In English speech, the numbers 19 and 90 are often confused. When carefully enunciated, they differ in which syllable is stressed: 19 /naɪnˈtiːn/ vs 90 /ˈnaɪnti/. However, in dates such as 1999, and when contrasting numbers in the teens and when counting, such as 17, 18, 19, the stress shifts to the first syllable: 19 /ˈnaɪntiːn/.

Mathematics

19 is a centered triangular number

19 is the 8th smallest prime number. The sequence continues 23, 29, 31, 37...

19 is the seventh Mersenne prime exponent.

19 is the aliquot sum of two odd discrete semiprimes, 65 and 77 and is the base of the 19-aliquot tree.

19 is a centered triangular number, centered hexagonal number and a Heegner number.

The largest normal magic hexagon contains 19 hexagons.

19 is the first number with more than one digit that can be written from base 2 to base 19 using only the digits 0 to 9; the other number is 20.^[1]

When a 3x3x3 cube is made of twenty-seven unit cubes, maximum 19 of them are visible.

Technology

• 19 is The TCP/IP port used for chargen.

Science

• The atomic number of potassium

Religion

Islam

• The number of angels guarding Hell ("Hellfire") according to the Qur'an: "Over it is nineteen" (74:30).
• The Number of Verse and Sura together in the Qur'an which announces Jesus son of Maryam's (Mary's) birth (Qur'an 19:19).
• Some people have claimed that patterns of the number 19 is present an unusual number of times in the Qurʾān.[1][2]

Baha'i faith

In the Bábí and Bahá'í faiths, a group of 19 is called a Váhid, a Unity (Arabic: واحد wāhid, "one"). The numerical value of this word in the Abjad numeral system is 19.

• The Bahá'í calendar is structured such that a year contains 19 months of 19 days each (along with the intercalary period of Ayyám-i-Há), as well as a 19-year cycle and a 361-year (19x19) supercycle.
• The Báb and his disciples formed a group of 19.
• There were 19 Apostles of Bahá'u'lláh.

Music

• 19 is the debut album from English soul and jazz singer Adele.
• 19 is the fourth studio album from Russian pop singer Alsou.
• 19 is Evan Yo's first album, because Yo was nineteen years old when the album was released.
• "19" is a 1985 song by Paul Hardcastle, including sampled soundbites taken from a documentary about the Vietnam War in which 19 is claimed to have been the average age of United States soldiers killed in the conflict (an assertion which is widely disputed).^[2] The song was parodied by British satirist Rory Bremner under the pseudonym 'The Commentators,' as N-n-nineteen, Not Out, the title referring to the batting average of David Gower, the England cricket captain, during his side's risible performance against the West Indies in 1984 when they lost 5-0.

• With a similar name and anti-Vietnam War theme, "I Was Only Nineteen" by the Australian group Redgum reached number one on the Australian charts in 1983. In 2005 a hip hop version of the song was produced by The Herd.
• Other songs titled 19:
  • "Nineteen" by Bad4good
  • "Nineteen" by Buck-O-Nine
  • "Nineteen" by Phil Lynott
  • "Nineteen" by the Old 97's
  • "Nineteen" by Tegan and Sara
  • "Nineteen" by Phil Lynott

• Nineteen has been used as an alternative to twelve for a division of the octave into equal parts. This idea goes back to Salinas in the sixteenth century, and is interesting in part because it gives a system of meantone tuning, being close to 1/3 comma meantone. See 19 equal temperament.

• Some organs use the 19th harmonic to approximate a minor third.

Literature

• Stephen King's seven book epic The Dark Tower saga employs the number 19 in books The Dark Tower: The Gunslinger, The Dark Tower V: Wolves of the Calla, and The Dark Tower VI: Song of Susannah as a mysterious and important number. They refer to the "ka-tet of 19", many names add up to 19, 19 seems to permeate every aspect of Roland and his traveler's lives. In addition, the number ends up being a powerful key.

• In Jodi Picoult's bestseller book Nineteen Minutes, the number 19 is referenced multiple times. It is most commonly referenced when referring to the main subject of the book, the school shooting rampage that took place over a span of 19 minutes.

Games

A 19x19 Go board

• The game of Go is played on a grid of 19×19 lines (though variants can be played on grids of other sizes).

• 19 is the command in Age of Empires for the laughing emote. This was an easier way to laugh before "LOL" existed.

• Though the maximum score for a cribbage hand is 29, there is no combination of cards that adds up to 19 points. Many cribbage players, therefore, jokingly refer to a zero-point hand as "19 points."

• In Ecuadorian card game "40", when counting the amount of cards gathered in a hand, the limit is 19, after which the count starts at 6 and represents the points achieved during that hand.

Age 19

• The final year a person is a teenager
• This is the minimum age that is legal to buy tobacco products in Alabama, Alaska, New Jersey, Utah, and Nassau, Suffolk, and Onondaga counties in New York.^[3]
• This is the minimum age at which one can drink and buy alcohol in Canada except for the provinces of Alberta, Manitoba, and Quebec where the drinking and purchase age of alcohol is 18.
• This is the minimum age to marry in the state of Nebraska.

Cars

• Renault 19, a car that was produced by French automobile manufacturer Renault.

Other fields

• The Nineteen Propositions was a 1642 petition from parliament to King Charles I of England.
• The nineteenth President of the United States was Rutherford B. Hayes.
• The nineteenth state to enter the Union of the United States was Indiana
• Part of the name of a breakfast cereal: Product 19
• The Soviet submarine K-19 was the first Soviet nuclear ballistic submarine
• I-19 is the designation for a US Interstate highway in Arizona
• 19 years is very close to 235 lunations. See Metonic cycle
• In golf the "19th hole" is the clubhouse bar. In miniature golf it is an extra hole on which the winner earns an instant prize
• A number retired by several teams in North American sports. (Except as noted, all players are in the Hall of Fame of their respective sport.)
  • In the NFL:
    • Lance Alworth, by the San Diego Chargers.
    • Johnny Unitas, by the Baltimore Colts. The team has honored this retirement in its current home of Indianapolis.
  • In Major League Baseball:
    • Bob Feller, by the Cleveland Indians.
    • Tony Gwynn, by the San Diego Padres.
    • Robin Yount, by the Milwaukee Brewers.
  • In the NBA:
    • Willis Reed, by the New York Knicks.
  • In the NHL:
    • Bill Masterton, by the Minnesota North Stars. The team has honored this retirement in its current home of Dallas. Masterton is not in the Hockey Hall of Fame; his number was retired after he died from an on-ice injury in 1968. He is the only NHL player to have died as a direct result of an injury suffered during an NHL game.
    • Larry Robinson, by the Montreal Canadiens.
    • Joe Sakic, by the Colorado Avalanche. Sakic is not yet eligible for the Hall of Fame, as he retired in 2009.
    • Bryan Trottier, by the New York Islanders.
    • Steve Yzerman, by the Detroit Red Wings. Some Red Wings fans collectively refer to themselves as "the 19" in his honor.[3]
• In the NASCAR Sprint Cup Series, 19 is the number of a car owned by Richard Petty Motorsports, a Ford Fusion with Best Buy as its primary sponsor, and driven by Elliott Sadler.
• The number of the French department Corrèze

Historical years

A.D. 19, 19 B.C., 1919, 2019, etc.

References

1. ^ Sequence A131646 in The On-Line Encyclopedia of Integer Sequences
2. ^ Roush, Gary (2008-06-02). "Statistics about the Vietnam War". Vietnam Helicopter Flight Crew Network. Archived from the original on 2009-12-06. http://www.vhfcn.org/stat.html. Retrieved 2009-12-06. "Assuming KIAs accurately represented age groups serving in Vietnam, the average age of an infantryman (MOS 11B) serving in Vietnam to be 19 years old is a myth, it is actually 22. None of the enlisted grades have an average age of less than 20." 
3. ^ Center for Health Improvement (2008-06-02). "Minimum Age Increase". Archived from the original on 2009-07-22. http://worldstatesmen.org/USA_govt.html#Justice. Retrieved 2004-06-30. "In Alabama, Alaska, and Utah, 19 years is the minimum age for sale of tobacco products" 

External links

• Number 19 at the Database of Number Correlations
• Prime Curios for the number 19