From Wikipedia, the free encyclopedia
65 (sixty-five) is the natural number
following 64 and
preceding 66.
In
mathematics
Sixty-five is the 19th semiprime and the 3rd of
the form (5.q)it is an octagonal number. It is also a Cullen number.
Given 65, the Mertens function returns 0.
Sixty-five has an aliquot sum of 19 and
is the first composite number in the 19-aliquot tree.
This number is the magic constant of 5 by 5 normal magic square:
This number is also the magic constant of n-Queens
Problem for n = 5.
65 is the smallest integer that can be expressed as a sum of two
distinct positive squares in two ways, 65 = 8^{2} +
1^{2} = 7^{2} + 4^{2}.
It appears in the Padovan sequence, preceded by the
terms 28, 37, 49 (it is the sum of the first two of these).
There are only 65 known Euler's idoneal
numbers.
65=1^{5}+2^{4}+3^{3}+4^{2}+5^{1}
In
science
Astronomy
- The Saros number of the solar eclipse
series which began on -749 April 24 and ended on 513 May. The
duration of Saros series 65 was 1262.1 years, and it contained 71
solar eclipses.
- The Saros number of the lunar eclipse
series which began on -736 August 11 and ended on 797 February. The
duration of Saros series 65 was 1532.5 years, and it contained 86
lunar eclipses.
In other
fields
Sixty-five is:
- A common speed
limit, in miles per hour, for freeways in many U.S. states,
primarily in the eastern United States (in the western United
States, the common limit is 70 and in some places 75)
- The designation of Interstate 65, a freeway that runs from
Alabama to Indiana
- Municipal Okrug 65, a municipal okrug of Primorsky District of
Saint
Petersburg, Russia
- +65 is the
code
for international direct dial phone calls to Singapore
- The traditional age for retirement in the United Kingdom, Germany and other countries. It was previously
the age at which a person in the United States could retire with full Social Security
benefits; however, recent changes in the law have increased this
age for younger workers due to improvements in life expectancy
- The registry of the U.S. Navy's nuclear aircraft carrier USS
Enterprise (CVN-65)
- 65 is the minimum grade required to pass an exam, or class, in
many areas
- Paul
Davis had a hit song "65 Love Affair" in
1982
- Sammy Hagar
re-recorded his hit "I Can't Drive 55", with the 55 changed to 65,
in 2001 for NBC's NASCAR
broadcasts to reflect higher speed limits. The song was used from
2001 until 2004 to introduce Budweiser Pole Award winners on NBC
and TNT broadcasts.
- 65 is a commonly used abbreviation for the Sheffield, UK, post-rock band 65daysofstatic.
- The setting of Naked City (1958 - 63) was
New York's 65th Precinct
- Referenced in "Heroes and Villains" by the Beach Boys:
"At threescore and
five / I'm very much
alive / I've still got the jive / to survive with the Heroes and
Villains."
- The number of the French department Hautes-Pyrénées
In sports
Historical
years
65 A.D., 65 B.C., 1965, 2065, etc.