47 Is A Special Number

47 is indeed a special number.

Today (November 11, 2007) I have turned 47 years old -- it is my birthday today.

Although I am not a "numerologist" nor a "number theorist", I would like to think that numbers can be fun :)

For example, I found today a website about some interesting facts on the number 47. It's title is Prime Curios! and the website address is http://primes.utm.edu/curios/page.php/47.html

I would like to reproduce some information (from the website) about the number 47 in this blog:

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There are 47 occurrences of 47 in the first thousand prime numbers. [Faust]

Tyrannosauras rex measured up to 47 feet in overall length. [Norris]

It is interesting that the product of 4 consecutive Fibonacci numbers can equal the product of the first 7 primes.

In the Pixar Film Monsters Inc., the scream factory had enjoyed 47 accident-free days at the start of the movie. [Hartley]

There is an abnormally high use of the prime number 47 in episodes of Star Trek.

The houseband for New York City called Black 47 reside on 47th Street.

The British liner Great Eastern had a coir fiber launching rope with a circumference of 47 inches.

The AK-47 is the most widespread weapon in the world. [Kalashnikov]

479 can be written as the sum of distinct smaller 9th powers.

66647 has a digit sum of 666. [De Geest]

Auguste Comte coined the word sociology, which appeared for the first time in a footnote to the 47th lesson of the fourth volume of his Course of Positive Philosophy.

43 + 73 = 407.

47 x 2583 + 1, 47 x 21483 + 1 and 47 x 26115 + 1 are the only known primes of the form 47 x 2n + 1. [Ballinger & Keller]

John Major was 47 years old when he became British Prime Minister.

47 is a prime Keith number.

The MK-47 was the first and last Soviet calculator with magnetic cards. [Frolov]

47 is self-conscious: 4 + 7 = 11, 7 + 11 = 18, 11 + 18 = 29, and 18 + 29 = 47. It refers to itself. Note that 4, 7 and 47 are Lucas numbers. [Faust]

The Declaration of Independence contains 47 sentences. [Hammonds]

47 is the first and only prime p less than 20000 of the form p*2^(p+1)-1, where p is prime. [Luhn]

Lot 47 Inc. is a privately owned film company focused on the acquisition and distribution of American independent films as well as high-profile foreign films.

Marine Storm Warnings occur with forecast winds greater than 47 knots. [NOAA]

The translation of the Bible (KJV) was made by 47 scholars. [English]

"The number 47 may be a flying increment to fill allspace, to fill out the eight triangular facets of the non-allspace-filling vector equilibrium to form the allspace-filling first nuclear cube." (Quoted from section 1238.51 of Synergetics by R. Buckminster Fuller.) [Croll]

47 + 2 equals the reversal of 47 * 2.

There are 47 Pythagorean propositions in Euclid's Elements. [Dobb]

It is approximately 47 degrees from the Tropic of Cancer (the greatest distance north that the sun can appear directly overhead) to the Tropic of Capricorn (the greatest distance south that the sun can appear directly overhead). [Obeidin]

New Jersey is ranked 47 in total land area among States in the Union.

Isaac Asimov's Book of Facts mentions the "fact" that mosquitoes have 47 teeth. [Patterson]

The gyroelongated pentagonal cupolarotunda has 47 faces. It is the largest prime number of faces a Johnson solid can have. [Hartley]

47 is the largest known number, n, such that n and n + 1 are both Ulam numbers. [McCranie]

The 47 Society is a humorous society at Pomona College in California that propagates the belief that the number 47 is the quintessential random number. Campus lore suggests that Pomona math professor Donald Bentley produced a convincing mathematical proof that 47 was equal to all other integers.

There are an incredible number of references to the number 47 in the TV show Alias. [Hunt]

A fifteenth century Chinese official named Wan-Hoo attempted a flight to the Moon using two kites fastened to a sedan chair on which he had strapped 47 black powder rockets. 47 servants simultaneously lit the fuses and Wan-Hoo disappeared in a burst of flame and smoke. [Caldwell]

The surprising formula for primes proposed by J. Minac and C. Willans in 1995 had 47 symbols. This formula, based on Wilson theorem, gives all the primes successively and without repetition, but unfortunately is not very convenient. [Capelle]

47 bones of the "Lucy" skeleton were unearthed in '74.

473 is the smallest cube which is sum of consecutive squares. Note that the following cube with this property is also prime. [Capelle]

The modern concert harp has 47 strings. [Kamath]

Only 47 printed copies of the Gutenberg Bible are still in existence.

ceil(( + e/47)^47) is prime. [Noll]

A prime number that has its own fan club (www.47.net). [Schuler]

Mary Mallon, better known as "Typhoid Mary," was a food service worker who infected 47 people with the bacterium Salmonella enterica typhi.

The Hadwiger Problem asks for the largest number of subcubes (not necessarily different) into which a cube cannot be divided by plane cuts. The answer is 47. [Post]

Mathematician Kevin Hare has proven that any odd perfect number must have at least 47 prime factors, including repetitions.

47 is the smallest prime whose number of perfect partitions is greater than itself. [Beedassy]

In the play The Five Hysterical Girls Theorem by Rinne Groff, renowned number theorist Moses Vazsonyi fears that he has lost his edge in the intellectually grueling world of prime number theory at the age of 47.
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Cheers,

Raffy
11/11/07