A page of the __Numeropedia - the Special Encyclopedia of Numbers__

[20-29]: 20 - 21- 22 - 23 - 24 - 25 - 26 - 27 - 28 - 29

All Numbers & [0-9] & 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99 100

1 - 10 - 100 - 1000 - 10,000 - 100,000 - 1M - 10M - 100M - 1B - 10B - 100B - 1T - 10T - 100T - 1Q - ...

[Biology] The number of ribs on a human skeleton (12 pairs).

[Calendar] The number of leap years in the 17^{th}, 18^{th}, 19^{th} or 21^{st} centuries, following the adoption of the current Gregorian calendar, created by Pope Gregory XIII to reform the old Julian calendar in the 16^{th} century (1582).

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[Calendar] The number of hours in a day. 1 week = 7 days = 168 hours = 10,080 minutes = 604,800 seconds.

[Calendar] The United Nations Day is on 24 October.

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[Chemistry] The atomic number of Chromium (Cr).

[EECS] 24(W, KW or MW) is one of standard numerical values for resistors (of tolerance class 5%). 24pF (picofarads) is one of standard numerical values for capacitors.

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[Flag] The number of stars forming a circle encircling the seal on the Missouri state flag, representing the 24^{th} state of the Union.

[Flag] The number of golden spikes/triangles encircling the blazing sun on the South Dakota state flag.

[Flag] The number of rays radiated from the golden sun, at the upper corner of the fly end, on the national flag of Rwanda.

[Flag] The number of rays radiated from the white star, 20 small rays and 4 large rays, near the hoist side above the two strips (orange on top of white), on the national flag of Marshall Islands.

[Game] The number of triangular points on a backgammon board: 12 for each color or also 12 for each side of the board. Each player has 15 counters at the start of the game.

[Game] The number of prize wedges on the wheel of the TV show "Wheel of Fortune".

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[Geology] The number of time zones, theoretically with equal widths, in the [World], first proposed by Sir Sanford Fleming (Canadian) in 1878, officially adopted on 1 November 1884 at the International Meridian Conference in Washington, D.C.

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[Geology] The length (miles) of the longest bridge over water in the U.S. (or the world): the Lake Pontchartrain Causeway, in Louisiana, connecting Metairie with St. Tammany Parish on the North shore.

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[History] Missouri became the 24^{th} state of the U.S. on 10 August 1821.

[History] The 24^{th} and 22^{nd} U.S. President: Grover Cleveland (Democrat, New Jersey, 1885-1889 and 1893-1897).

[Language] The number of letters in the Greek alphabet (written in name/capital/small): Alpha A α, Beta B β, Gamma Γ γ, Delta Δ δ, Epsilon Ε ε, Zeta Ζ ζ, Eta Η η, Theta Θ θ, Iota Ι ι, Kappa Κ κ, Lambda Λ λ, Mu Μ μ, Nu Ν ν, Xi Ξ ξ, Omicron O ο, Pi Π π, Rho Ρ ρ, Sigma Σ σ, Tau Τ τ, Upsilon Υ υ, Phi Φ φ, Chi X χ, Psi Ψ ψ and Omega Ω ω. There are 7 vowels: A, E, H, I, O, Y and Ω.

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[Math.] 4 factorial = 4! = 1×2×3×4 = 24.

[Math.] The number of 0’s that the factorial (100!) ends in: 24 = [[100/5]]+[[100/5^{2}]], where [[*x*]] is the floor function of *x*, i.e. which is the largest integer less than *x* (or the integral part of *x*).

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[Math.] 72 = 24×3 and, reversely, 27 = 24+3.

[Math.] The *only* pyramidal number that is a square: 1^{2}+2^{2}+…+23^{2}+24^{2} = 4900 = 70^{2}. It is sometimes called a perfect square (or a squared square). This is the only non-trivial solution of Watson’s equation: 1^{2}+2^{2}+…+*x*^{2} = *y*^{2}. However, there are many solutions of the equation (*n*+1)^{2}+(*n*+2)^{2}+…+(*n*+*x*)^{2} = *y*^{2}.

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[Math.] Its odd powers end with 24. Its even powers end with 76.

[Math.]

12×21 = 252 = 21×12

12×42 = 504 = 21×24 24×21 = 504 = 42×12

12×63 = 756 = 21×36 24×63 = 1,512 = 42×36

12×84 = 1,008 = 21×48 24×42 = 1,008 = 42×24

36×84 = 3,024 = 63×48 24×84 = 2,016 = 42×48.

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[Math.] A base system of multigrade equalities:

1+6+6+11 = 24 = 2+3+9+10

1^{2}+6^{2}+6^{2}+11^{2} = 194 = 2^{2}+3^{2}+9^{2}+10^{2} and

1^{3}+6^{3}+6^{3}+11^{3} = 1764 = 2^{3}+3^{3}+9^{3}+10^{3}. (References [??])

Multigrade equalities still hold by adding any integer *n* to every base term in both sides. Hence, the base equality always has number 1 appearing in one side.

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[Measure] The number of furlongs in a league (old British imperial units for distance measures).

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[Measure] The number of sheets of paper in a quire. (24 or 25).

[Measure] The number of grains in a pennyweight.

Units for precious metals weight measures: 1 troy pound = 12 troy ounces = 240 pennyweights = 5760 grains = 373 *g *(grams).

[Measure] 1 ounce apothecaries = 24 scruples. 1 pound apothecaries = 12 ounces apothecaries = 96 drams apothecaries = 288 scruples = 5760 grains.

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[Measure] Length of a person’s forearms, from the elbow to the middle finger tips, is cubit: 1 cubit = 6 palms = 24 digits = 18 inches = 457.2 *mm*. A digit is the width of one finger, ¾ of an inch, 19.05 *mm*. Roman cubit: 17.5 inches = 444.5 *mm*. Egyptian cubit = 20.63 inches = 524 *mm* = 27.5 digits or often 28 digits.

[Measure] Pure gold is 24 karats, which is the maximum scale (karats or carats) for measuring the purity of gold. E.g., “14-karat gold” is legally at least 14/24 or 58.33% pure gold.

[Movie] Names of TV show/series or movie: “24” and “24: Redemption”.

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[Music] The number of pairs of holes on a standard (full-size) harmonica.

[Science] Prefix: Yotta- = 10^{24}.

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[Science] The number of names of tropical cyclones in the Eastern North Pacific basin in the list for a year. There are six such lists used in rotation. The names are in alphabetical order, excluding the 2 letters: Q and U.

[Sport] In a NBA (National Basketball Association) game, the team gaining possession of the ball must move it passing the haft court line within 8 seconds and must attempt a field goal (i.e. the ball must at least touch the basket’s rim) within 24 seconds.

[Sport] The number of footballs that the home team must provide the referee for each NFL (National Football League) game.

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[Tech.] One of the standardized numbers of exposures in a roll of 35-*mm* camera films: 12 – 24 – 36.

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[Trivia] Pack of soft drink cans or bottles: 4, 6, 12, 18, 20, 24, 30 or 36.

[Trivia] The number of eggs in a carton: 6, 12, 18 or 36.

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[Trivia] The U.S. 24-cent “Inverted Jenny” stamp is the world’s most famous philatelic error, which printed the Curtiss NJ-4H “Jenny” aircraft upside down, in the first U.S. airmail stamp of the year 1918. Only one such flawed sheet of 100 stamps was sold in a Washington, D.C.

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[Trivia] 7/24 or 24/7 means being open 24 hours day, 7 days a week.

[Trivia] Military curfew is 24/24.

[World] The ISO country code for Angola is 024. (ISO-3166)

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[Science]

American system |
British system |
Number |

***** |
tredecillion |
10 |

tredecillion |
septillion |
10 |

septillion |
quadrillion |
10 |

quadrillion |
***** |
10 |

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**24 **&** 23 **and** 22 **&** 21**

[History] The 22^{nd} and 24^{th} U.S. President: Stephen Grover Cleveland (Democrat, New Jersey, 1885-1889 and 1893-1897).

His Vice President of the 24^{th} Presidency, Adlai Ewing Stevenson (Illinois, 1893-1897), was the 23^{rd} U.S. Vice President.

His Vice President 22^{nd} Presidency, Thomas Andrews Hendricks (Indiana, 1885), was the 21^{st} U.S. Vice President. There was no Vice President in the period 1885-1889.

**25** & **24**

[History] The 25^{th} U.S. President: William McKinley (Republican, Ohio, 1897-1901).

His Vice Presidents were: Garret Augustus Hobart (New Jersey, 1897-1901), the 24^{th} U.S. Vice President and Theodore Roosevelt (New York, 1901), the 25^{th} U.S. Vice President.