66 (number) - Definition and Overview

66 is the natural number following 65 and preceding 67.

In mathematics

66 is a sphenic number, a triangular number, a hexagonal number, and a semi-meandric number.

In science

• The atomic number of dysprosium, a lanthanide

In astronomy,

Messier object M66, a magnitude 10.0 galaxy in the constellation Leo

The New General Catalogue object (http://www.ngcic.org/) NGC 66, a peculiar barred spiral galaxy in the constellation Cetus

The Saros number (http://sunearth.gsfc.nasa.gov/eclipse/SEsaros/SEsaros1-175.html) of the solar eclipse series which began on -756 March 12 and ended on 542 May 1. The duration of Saros series 66 was 1298.1 years, and it contained 73 solar eclipses.

The Saros number (http://sunearth.gsfc.nasa.gov/eclipse/LEsaros/LEsaros1-175.html) of the lunar eclipse series which began on -671 August 12 and ended on 826 January 27. The duration of Saros series 66 was 1496.5 years, and it contained 84 lunar eclipses.

In other fields

66 is also:

• The designation of the historic Route 66, dubbed the "Mother Road" by novelist John Steinbeck.
• The designation of US Interstate 66, a freeway that runs from Virginia to Washington, D.C..
• The number of the French department Pyrénées-Orientales.
• The international direct dialling (IDD) code for Thailand.
• The year AD 66, 66 BC, or 1966.
• The name of a German card game, translated from sechsundsechzig.
• Sexual slang for anal sex.
• Number of the Hockey legend Mario Lemieux