66 (sixty-six) is the natural number following 65 and preceding 67.

Cardinal	66 sixty-six
Ordinal	66th sixty-sixth
Factorization	$2\; \backslash cdot\; 3\; \backslash cdot\; 11$
Divisors	2, 3, 6, 11, 22, 33
Roman numeral	LXVI
Binary	1000010
Hexadecimal	42

In mathematics

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

In science

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• The atomic number of dysprosium, a lanthanide

In astronomy,

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

The New General Catalogue object NGC 66, a peculiar barred spiral galaxy in the constellation Cetus

The Saros number 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 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 sports

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• 66 is the number belonging to hockey great, Mario Lemieux of the Pittsburgh Penguins.

In other fields

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66 is also:

• The year AD 66, 66 BC, or 1966.
  • 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 designation of 36 state and 2 territorial highways (see Route 66 (disambiguation).
  • The international direct dialing (IDD) code for Thailand.
  • The number of the French department Pyrénées-Orientales.
  • The name of a German card game, translated from sechsundsechzig.
  • The total number of books in the Protestant edition of the Bible (Old Testament and New Testament combined).
  • In Abjad numerals, The Name Of Allah (الله) numeric value is 66.
  • In Star Wars, Order 66 is a prepared order to the clone troopers to kill the Jedi commanding them.

  The number 66 seems important in British history. There are three key events that occurred in a year with this ending. They are:

  • 1066 - Norman conquest
  • 1666 - Great Fire of London
  • 1966 - England win the World Cup

  Integers

  Sesenta y seis | Sesdek ses | 66 (nombre) | 66 | 66 | Sessantasei | 66 (skaičius) | 66 (getal) | 66 | Sessenta e seis | 66 (число) | 66 (število) | 66 (tal) | 66