Thirty
From Wikipedia, the free encyclopedia.

30 (thirty) is the natural number following twenty-nine and preceeding thirty-one.

30
Cardinal	thirty
Ordinal	thirtieth
Numeral system
Factorization
Roman numeral	XXX
Binary	11110
Hexadecimal	1E

Mathematics

It is a primorial as well as the sum of the squares of the integers 1, 2, 3 and 4. It is a sphenic number. Its divisors are 1, 2, 3, 5, 6, 10, 15 and 30.

The Chinese word numeral for thirty is 三十; a polygon with thirty sides is called a tricegon. [1]

Other fields

Thirty is:

• The atomic number of zinc.
• The number of edges on the regular icosahedron and the regular dodecahedron.
• The house number of 30 St Mary Axe (The Gherkin)
• The number of days in the months April, June, September and November.
• The number of moons of the planet Saturn.
• In years of marriage, the pearl wedding anniversary.
• The code for international direct dial phone calls to Greece.
• The designation of Interstate 30, a freeway that runs from Texas to Arkansas.
• Part of the name of:
  • Thirty odd foot of grunts, the band fronted by actor Russell Crowe
• The year AD 30.

29 and 31

The original article can be found at: http://en.wikipedia.org/wiki/Thirty.
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