A page of the Numeropedia - the Special Encyclopedia of Numbers
[Tech.] 1 mechanical/regular/traditional horsepower (hp) = 550 ft×lb/s (feet×pound/second), exactly. (Definition: Work for lifting 550 lb, one foot high in the air in one second or 745.7 W (watts).
[Measure] 1 dry pint = 550.6105 ml (milliliters).
U.S. customary units for dry measures: 1 bushel = 4 pecks = 32 dry quarts = 64 dry pints = 35.23907016688 liters = 2150.42 inch3.
[History] The year (551B.C) Confucius was born in China.
[Library] ISBN-0-553 is the International Standard Book Number for books published by Bantam Books.
[Geology] The CN Tower, a 553.33-meter (1,815 feet 5 inches) communications structure and outlook point in Toronto, Canada, is the highest freestanding tower (as of 2005). The Taipei 101, the tallest building in the world in 2003: 101 stories and 1667 feet tall (508-meter).
[World] The ISO-3166 country code for New Zealand.
[History] The height (feet) of the Washington Monument in Washington, D.C., opened to public in 1888.
[Phone] The number to key in text messaging on telephone keypad for letter L.
[Phone] The 7-digit telephone numbers 555-01nn, where nn = 00, 01,…, 99 are reserved for fictitious use (like movies, novels…). There is no telephone area code 555.
[Science] 1 lumen = 1/683 watts at the light wavelength 555 nm (nanometers), the wavelength usually referred to be the most sensitive to human eyes.
[Tech.] A popular clock timer chip, made originally by Signetics, implementing a variety of multi-vibrator applications, and historically widely used in electronics. Later there are other versions: 556 dual chips and 558 quad chips.
[Tech.] A popular cigarette brand name from England.
[Geology] The number of officially recognized native American tribes. (to be Verified)
[Math.] Numbers of the same pattern, xxy, where y = x +1: 1122 = 012,544 & 012+544 = 556 & 5562 = 309,136 & 309+136 = 445 & 4452 = 198,025 & 198+025 = 223 & 2232 = 049,729 & 049+729 = 778 & 7782 = 605,284 & 605+284 = 889 & 8892 = 790,321 & 790+321 = 1111. Also: 3342 = 111556 & 111+556 = 667.
[Math.] A prime number.
[Tech.] The number of commercial airports in the U.S., as of 2003.
[World] The ISO-3166 country code for Nicaragua.
[Tech.] The shorter side (mm, millimeters) of the U.S. standard paper of size D, for technical drawing, 864 mm×559 mm. It is half of size E, 1118 mm×864 mm.
[Library] Numbers 500-599 are the first 3 digits in Dewey Decimal Classification System call numbers for library books in Pure Sciences (Mathematics, Astronomy and Chemistry…). Numbers 550-559 are for books in Earth Sciences.