84 (eighty-four) is the natural number following 83 and preceding 85. Natural number can mean either a positive integer (1, 2, 3, 4, ...) or a non-negative integer (0, 1, 2, 3, 4, ...). Natural numbers have two main purposes: they can be used for counting (there are 3 apples on the table), or they can be used for ordering (this is... 83 is the natural number following 82 and preceding 84. ... 85 is the natural number following 84 and preceding 86. ...

In linguistics, cardinal numbers is the name given to number words that are used for quantity (one, two, three), as opposed to ordinal numbers, words that are used for order (first, second, third). ... Commonly, ordinal numbers, or ordinals for short, are numbers used to denote the position in an ordered sequence: first, second, third, fourth, etc. ... This article is about the mathematical concept. ... In mathematics, a divisor of an integer n, also called a factor of n, is an integer which evenly divides n without leaving a remainder. ... The system of Roman numerals is a numeral system originating in ancient Rome, and was adapted from Etruscan numerals. ... The binary or base-two numeral system is a system for representing numbers in which a radix of two is used; that is, each digit in a binary numeral may have either of two different values. ... In mathematics and computer science, hexadecimal or simply hex is a numeral system with a radix or base of 16 usually written using the symbols 0–9 and A–F or a–f. ...

In mathematics

Eighty-four is the sum of the first seven triangular numbers (making it a tetrahedral number), as well as the sum of a twin prime (41 + 43). A triangular number is a number that can be arranged in the shape of an equilateral triangle. ... A tetrahedral number, or triangular pyramidal number, is a figurate number that represents a pyramid with a base and three sides, that is, a tetrahedron. ... A twin prime is a prime number that differs from another prime number by two. ...

In astronomy

• Messier object M84, a magnitude 11.0 lenticular galaxy in the constellation Virgo
• The New General Catalogue object (http://www.ngcic.org/) NGC 84, a single star in the constellation Andromeda
• The Saros number of the solar eclipse series which began on -181 April 14 and ended on 1099 May 22. The duration of Saros series 84 was 1280.1 years, and it contained 72 solar eclipses. Further, the number of the lunar eclipse series which began on -96 September 13 and ended on 1401 February 28. The duration of Saros series 84 was 1496.5 years, and it contained 84 lunar eclipses.

Table of all 110 Messier objects. ... The Lenticular Galaxy M84 (also known as Messier Object 84, Messier 84, M84, or NGC 4374) is a lenticular galaxy in the Virgo constellation. ... The apparent magnitude (m) of a star, planet or other heavenly body is a measure of its apparent brightness; that is, the amount of light received from the object. ... The Spindle Galaxy (NGC 5866), a lenticular galaxy in the Draco constellation. ... Orion is a remarkable constellation, visible from most places on the globe (but not always the whole year long). ... See VIRGO (physics) for a French-Italian project in physics. ... The New General Catalogue (NGC) is the most well-known catalogue of deep sky objects in amateur astronomy. ... Andromeda is a constellation named for the princess Andromeda (which is Greek for Ruler over men), a character in greek mythology. ... A Saros cycle is a period of 6585 + 1/3 days (approximately 18 years 10 days and 8 hours) which can be used to predict eclipses of the sun and the moon. ... Photo taken by John Walker during the Zambia 2001 eclipse A solar eclipse occurs when the Sun, Moon and Earth are on a single line with the Moon in the middle. ... April 14 is the 104th day of the year in the Gregorian calendar (105th in leap years). ... Events Siege of Jerusalem during the First Crusade: July 8 - 15,000 starving Christian soldiers march around Jerusalem as its Muslim defenders mock them. ... May 22 is the 142nd day of the year in the Gregorian calendar (143rd in leap years). ... An eclipse occurs whenever the Sun, Earth and Moon line up exactly. ... September 13 is the 256th day of the year (257th in leap years). ... Events The Lollards, a religious sect taught by John Wycliffe, were persecuted for their beliefs. ... February 28 is the 59th day of the year in the Gregorian calendar. ...

In other fields

dial +84 for Vietnam

Eighty-four is also: nga van-nga son -thanh hoa File links The following pages link to this file: Vietnam 84 (number) User:DanielZm/test Template:Vietnam infobox ... nga van-nga son -thanh hoa File links The following pages link to this file: Vietnam 84 (number) User:DanielZm/test Template:Vietnam infobox ... This is a list of country calling codes, also known as international direct dialing (IDD) codes, which are needed to access international telephone services. ...

• The atomic number of polonium
• the model number of AGM-84 Harpoon
• WGS 84 - The latest revision of the World Geodetic System, a fixed global reference frame for the Earth.
• the house number of 84 Avenue Foch
• the number of the French department Vaucluse
• the designation of Interstate 84, two Interstate Highways that run from Oregon to Utah and from Pennsylvania to Massachusetts.
• the code for international direct dial phone calls to Vietnam
• a town in Pennsylvania: Eighty Four, named after the Eighty Four Lumber company
• The ISBN Group Identifier for books published in Spain
• The year AD 84, 84 BC, or 1984.

The atomic number (Z) is a term used in chemistry and physics to represent the number of protons found in the nucleus of an atom. ... General Name, Symbol, Number Polonium, Po, 84 Series Metalloids Group, Period, Block 6 (VIA), 6, p Density, Hardness 9196 kg/m3, no data Appearance silvery Atomic properties Atomic weight [209] u Atomic radius (calc. ... The AGM-84 Harpoon is a US all-weather, over-the-horizon, anti-ship missile system. ... WGS 84 is the 1984 revision of the World Geodetic System. ... Number 84 Avenue Foch was a building in Paris used by the German Gestapo during their occupation of Paris in World War II. The location is found on Avenue Foch, a wide residential boulevard in the 16e arrondissement which connects the Arc de Triomphe and the Porte Dauphine. ... The départements (or departments) are administrative units of France, roughly analogous to British counties and are now grouped into 22 metropolitan and four overseas régions. ... For other uses of the name Vaucluse, see Vaucluse (disambiguation) Vaucluse is a département in the south of France. ... Interstate 84 is the designation of two interstate highways in the United States. ... A typical rural stretch of Interstate highway, with two lanes in each direction separated by a large grassy median, and with cross-traffic limited to overpasses and underpasses. ... State nickname: Beaver State Other U.S. States Capital Salem Largest city Portland Governor Ted Kulongoski Official languages None Area 255,026 km² (9th)  - Land 248,849 km²  - Water 6,177 km² (2. ... State nickname: Beehive State Other U.S. States Capital Salt Lake City Largest city Salt Lake City Governor Jon M. Huntsman, Jr. ... State nickname: The Keystone State Other U.S. States Capital Harrisburg Largest city Philadelphia Governor Ed Rendell Official languages None Area 119,283 km² (33rd)  - Land 116,074 km²  - Water 3,208 km² (2. ... State nickname: Bay State Other U.S. States Capital Boston Largest city Boston Governor Mitt Romney Official languages English Area 27,360 km² (44th)  - Land 20,317 km²  - Water 7,043 km² (25. ... This is a list of country calling codes, also known as international direct dialing (IDD) codes, which are needed to access international telephone services. ... State nickname: The Keystone State Other U.S. States Capital Harrisburg Largest city Philadelphia Governor Ed Rendell Official languages None Area 119,283 km² (33rd)  - Land 116,074 km²  - Water 3,208 km² (2. ... Eighty Four, PA is a small town approximately 25 miles southwest of Pittsburgh, PA. Eighty-four is accessible via highways 519 and 136. ... The International Standard Book Number, or ISBN (sometimes pronounced is-ben), is a unique1 identifier for books, intended to be used commercially. ... For other uses, see number 84. ... Centuries: 2nd century BC - 1st century BC - 1st century Decades: 130s BC 120s BC 110s BC 100s BC 90s BC - 80s BC - 70s BC 60s BC 50s BC 40s BC 30s BC Years: 89 BC 88 BC 87 BC 86 BC 85 BC - 84 BC - 83 BC 82 BC 81... 1984 is a leap year starting on Sunday of the Gregorian calendar. ...