16 (number) - Definition and Overview

16 (sixteen) is the natural number following 15 and preceding 17.

In mathematics

Sixteen is a composite number, its proper divisors being 1, 2, 4 and 8. It is the fourth power of two.

Sixteen is the only integer that equals <math>m^n<math> and <math>n^m<math>, for some unequal integral m and n (m=4, n=2, or vice versa). It has this property because <math>2^2=2\times2<math>. It is also equal to 2↑↑3, (using Knuth's up-arrow notation).

16 is a centered pentagonal number.

16 is the base of the hexadecimal number system, which is used extensively with computers.

In science

• The atomic number of sulfur

In astronomy,

Messier object M16, a magnitude 6.5 nebula/open cluster in the constellation Serpens, also known as the Eagle Nebula Cluster.

The New General Catalogue object (http://www.ngcic.org/) NGC 16, a magnitude 12.0 galaxy in the constellation Pegasus

The Saros number (http://sunearth.gsfc.nasa.gov/eclipse/SEsaros/SEsaros1-175.html) of the solar eclipse series which began on -2456 July 23 and ended on -941 January 18. The duration of Saros series 16 was 1514.5 years, and it contained 85 solar eclipses.

The Saros number (http://sunearth.gsfc.nasa.gov/eclipse/LEsaros/LEsaros1-175.html) of the lunar eclipse series which began on -2172 April 21 and ended on -874 June 8. The duration of Saros series 16 was 1298.1 years, and it contained 73 lunar eclipses.

In human affairs: Age 16

16 is the age limit for being allowed a driver's license in many US states and in Canada, and for getting an adult job in most states and provinces in those countries (as well as, complementarily, dropping out of school). It is also the age of consent for many jurisdictions around the world.

For its coming-of-age signification, it has inspired the titles of many songs, such as "Happy Birthday Sweet Sixteen", "You're Sixteen, You're Beautiful and You're Mine", "Sweet Little Sixteen" and "Sixteen Candles", the last of which was borrowed as the title of a John Hughes movie.

In other fields

There are sixteen ounces in an avoirdupois pound.

There are sixteen different personality types in all in the Myers-Briggs classification system.

A note played for one-sixteenth the duration of a whole note is called a semiquaver.

In the 16-bit era, 16-bit microprocessor ran 16-bit applications.

• Sixteen Kingdoms, part of Chinese history
• Canada's Yellowhead Highway is designated as Highway Sixteen.
• I-16 is the designation for a US interstate highway in Georgia.
• Historical years: 16 A.D., 16 B.C., or 1916
• The fighter jet, the F-16 Fighting Falcon.

External link

• An activist site for lowering the voting age to 16 (http://www.voteat16.com)