Number 40

A page of the Numeropedia - the Special Encyclopedia of Numbers

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[Trivia]  The 40th wedding anniversary is traditionally named ruby (or garnet) anniversary. Modernly, it may be replaced by only ruby.


[Calendar] Ascension Day is the Thursday, 40 days after Easter Sunday, observed in commemoration of Jesus Christ’s ascension into Heaven.


[Calendar]  Ash Wednesday (the first day of Lent) is 40 weekdays (not counting Sundays) before Easter, (or 46 days totally, if counting 6 Sundays). 

 Easter day is canonically the first Sunday after the 14th day of the lunar month (the nominal full moon) that falls on or after March 21st (the vernal equinox, nominally).


[Chemistry]  The atomic number of Zirconium (Zr).


[Flag]  The number of rays from the yellow sun at the center on the national flag of Kyrgyzstan, representing the 40 Kyrgyz tribes. The rays run counterclockwise on the observe side and clockwise on the other side. In the sun center is a red ring crossed by two sets of three stylized curves representing a roof of the traditional Kyrgyz yurt.


[Geology]  U.S. cities/towns whose names start with “Forty”: Forty Fort, Pennsylvania 18704.


[Geology]  I-40, a major U.S. West-East interstate highway, connecting Barstow, California to Wilmington, North Carolina, 2463 miles.


[Gov.]  The number of hours per week for a regular full-time working schedule in the U.S.


[History]  North Dakota and South Dakota became the 39th and 40th states of the U.S. on the same day: 2 November 1889.


[History]  The 40th U.S. President: Ronald Wilson Reagan (Republican, Illinois, 1981-1989).


[Language] Prefixes : Quadrage-.


[Language]  The only number, written in English, whose letters are in the English alphabetical order, “forty”. “One” is the only number, written in English, whose letters are in the English alphabetical backward order.


[Literature]  Forty thieves and Ali Baba is one of best-known stories in the “One Thousand and One Nights”.


[Literature]  Forty days and nights of the “Great Flood”.


[Math.]  The age limit for the recipients of the Fields Medal, considered by most mathematicians as the equivalence of the Nobel Prize. The Fields Medal was established by Canadian mathematician John Charles Field in 1924 and was bestowed at the opening session of the International Congress of Mathematicians (ICM). Lars Valerian Ahlfors (Finland, Harvard) and Jesse Douglas (U.S., MIT) were first awarded at the 1936 ICM. Two medals were then awarded once every 4 years since 1950 ICM and up to 4 medals can be awarded since the 1966 ICM.


[Math.]  The first number disproved a conjecture by the Swiss mathematician Leonhard Euler (1707-1783) that the formula n2+n+41 gives all prime numbers. When n = 40, then n2+n+41 = 1681 = 412 is not a prime number. Even though, for all values of n from 0, 1,…, 39, the numbers n2+n+41 are prime numbers. In fact, for other values of n from –40, –39, to –1, the numbers n2+n+41 are also prime numbers.


[Math.]  The square root of the number formed by n digits 4 followed by n digits 0 starts with n digits 6, decimal point, and n digits 3:

401/2 = 6.3…,

44001/2 = 66.33…,

4440001/2 = 666.333…,

444400001/2 = 6666.3333…



[Measure]  The number of rods in a furlong.

U.S. customary units for linear measures: 1 mile = 8 furlongs = 320 rods = 1,760 yards = 5,280 feet = 63,360 inches.


[Measure]  The number of fluidounces in a quart.

British imperial units for dry and liquid measures: 1 bushel = 4 pecks = 8 gallons = 32 quarts = 64 pints = 256 gills = 1280 fluidounces = 36.368736 liters.


[Measure]  The number of yards in a bolt of fabric.

1 bolt (fabric) = 32 ells = 40 yards = 1440 inches,

1 ell = 1.25 yards = 3.75 feet = 45 inches = 60 digits = 1143 mm.


[Movie]  Names of TV shows/series or movies: “40 Days and 40 Nights” and “The 40-Year-Old Virgin”.


[Phone]  International telephone dialing code for Romania.


[Science]  Fujita Scale for Tornado

Scale, Intensity

Wind Speed

F0, Gale

40-72 mph

F1, Moderate

73-112 mph

F4, Devastating

207-260 mph

F2, Significant

113-157 mph

F5, Incredible

261-318 mph

F3, Severe

158-206 mph

F6, Inconceivable

319-379 mph


[Science]  The rainbow can bee seen only in the morning or late afternoon, because this phenomenon can occur only when the Sun is 40 degree or less above the horizon.


[Sport]  The exact distance (40 km, kilometers) of the first marathon race at the first modern 1896 Olympic Games (Athens, Greece). It was standardized in the 1924 Olympic Games (Paris, France) at 42.195 km, to be the length first run during the 1908 Olympic Games (London, England). It is not an even distance in either kilometers or miles (26 miles 385 yards).


[Sport]  One of systematically numerical scores in a game of tennis: Love-15-30-40.


[Sport]  Deuce, derived from the French “a deux du jeu”, means “2 points away from winning a game of tennis or when both opponent players have the score 40.


[Sport]  In a NFL game, the offense team has 40 seconds between plays, i.e. to snap the ball to start a new play.


[Sport]  In baseball, the “40-40” club refers to players who have had both 40 home runs and 40 stolen bases in a single season.


[Tech.]  The powers of commercial incandescent light bulbs: 300W, 100W, 75W, 60W, 40W, 30W, 15W, 7.5W and 3W.


[Tech.]  The “number system” code of an EAN-13 barcode for German’s products: 40, 41, 42, 43 and 44.


[Tech.]  The numbers of automobile engine oil SAE viscosity: 20W-20 (-40, -50), 10W-30 (-40) and 5W-20 (-30).


[Trivia]  Popular U.S. city street speed limits: 15, 25, 30, 35, 40, 45 or 50 miles/hour.


 [Trivia]  The 40th wedding anniversary is traditionally named ruby (or garnet) anniversary. Modernly, it may be replaced by only ruby.


[World]  The ISO country code for Austria is 040. (ISO-3166).


37 & 39, 40

[History]  The 37th U.S. President: Richard Milhous Nixon (Republican, California, 1969-1974).

His Vice Presidents were: Spiro Theodore Agnew (Maryland, 1969-1973), the 39th U.S. Vice President and Gerald Rudolph Ford (Nebraska, 1973-1974), the 40th U.S. Vice President.  There was no Vice President in some period of 1973. 


40 & 43

[History]  The 40th U.S. President: Ronald Wilson Reagan (Republican, Illinois, 1981-1989).

His Vice President, George Herbert Walker Bush (Massachusetts), was the 43rd U.S. Vice President.

[Tech.]  (Verifying)...  The correct angle for the re-entry position of a NASA space shuttle is 40o. A higher angle may cause the shuttle to skip off the atmosphere and back into space. A smaller angle may burn it up in the atmosphere. (To Be Checked)