145 (number)

Short description: Natural number

← 144 145 146 →
← 140 141 142 143 144 145 146 147 148 149 → List of numbers — Integers ← 0 100 200 300 400 500 600 700 800 900 →
Cardinal	one hundred forty-five
Ordinal	145th (one hundred forty-fifth)
Factorization	5 × 29
Divisors	1, 5, 29, 145
Greek numeral	ΡΜΕ´
Roman numeral	CXLV
Binary	100100012
Ternary	121013
Quaternary	21014
Quinary	10405
Senary	4016
Octal	2218
Duodecimal	10112
Hexadecimal	9116
Vigesimal	7520
Base 36	4136

145 (one hundred [and] forty-five) is the natural number following 144 and preceding 146.

In mathematics

• Although composite, 145 is a Fermat pseudoprime to sixteen bases with b < 145. In four of those bases, it is a strong pseudoprime: 1, 12, 17, and 144.
• Given 145, the Mertens function returns 0.
• 145 is a pentagonal number and a centered square number.
• [math]\displaystyle{ 145 = 12^2 + 1^2 = 8^2 + 9^2 }[/math]. 145 is the fourth number that is the sum of two different pairs of squares. Also, 145 is the result of 3⁴ + 4³, making it a Leyland number.
• [math]\displaystyle{ 145 = 1! + 4! + 5! }[/math], making it a factorion. The only other numbers that have the property that they are the sum of the factorials of their digits are 1, 2 and 40585.
• [math]\displaystyle{ 145=5^2+5!=11^2+4!=12^2+1! }[/math], making 145 the smallest number that can be written as the sum of a perfect square and a factorial in exactly 3 distinct ways. The next number with this property is 46249.

In the military

• USS Armada (AM-145) was a United States Navy Admirable-class minesweeper during World War II
• USS Colbert (APA-145) was a United States Navy Haskell-class attack transport during World War II
• USS General Harry Taylor (AP-145) was a United States Navy General G. O. Squier-class transport during World War II
• USS Greer (DD-145) was a United States Navy Wickes-class destroyer during World War II
• USS Huse (DE-145) was a United States Navy Edsall-class destroyer escort during World War II
• USS Roanoke (CL-145) was a United States Navy Worcester-class cruiser following World War II

In sports

• The Grand Union Canal Race is a 145-mile ultramarathon from Birmingham to London along the Grand Union Canal

In transportation

• Eurocopter EC 145 is a twin-engine light utility helicopter
• The Delahaye 145 Sports Car from 1938
• The Alfa Romeo 145 car produced between 1994 and 2001
• Volvo 145 Express station wagon
• ERJ 145 regional jets produced by Embraer
• Golden Gate Transit Bus Route 145
• London Bus Route 145

In other fields

145 is also:

• The year AD 145 or 145 BC
• 145 AH is a year in the Islamic calendar that corresponds to 762 – 763 CE
• 145 Adeona is a large main belt asteroid
• Psalm 145
• Sonnet 145
• Apple Computer laptops, such as the PowerBook 145 and PowerBook 145B
• Puff Daddy song “Picture it” includes the lyrics “in something foreign soarin’ 145”
• Tsuu T'ina Nation 145 Indian reserve in Alberta, Canada
• 145 mg medicine tablets, as with Tricor
• "One Four Five" is a song by The Cat Empire

See also

• List of highways numbered 145
• United Nations Security Council Resolution 145
• United States Supreme Court cases, Volume 145

References

• Wells, D. The Penguin Dictionary of Curious and Interesting Numbers London: Penguin Group. (1987): 140

External links

• The Natural Number 145
• Parker, Matt. "145 and the Melancoil". Numberphile. Brady Haran. http://www.numberphile.com/videos/melancoil.html.