|Factorization||5 × 13|
|Divisors||1, 5, 13, 65|
65 is the smallest integer that can be expressed as a sum of two distinct positive squares in two ways, 65 = 82 + 12 = 72 + 42.
There are only 65 known Euler's idoneal numbers.
65 = 15 + 24 + 33 + 42 + 51.
65 is the length of the hypotenuse of 4 different Pythagorean triangles, the lowest number to have more than 2: 652 = 162 + 632 = 332 + 562 = 392 + 522 = 252 + 602. The first two are "primitive", and 65 is the lowest number to be the largest side of more than one such triple.
- Messier object M65, a galaxy of magnitude 10.5 in the constellation Leo
- The New General Catalogue object NGC 65, a spiral galaxy in the constellation Cetus
- "65 Love Affair", singer Paul Davis' hit song 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
- Referenced in "Heroes and Villains" by the Beach Boys: "At 60 and 5 / I'm very much alive / I've still got the jive / to survive with the Heroes and Villains"
- Odd Future group MellowHype has performed a song entitled "65"
In other fields
- 65 miles per hour is a common speed limit on expressways in many U.S. states, primarily in the eastern and central United States. (In the western United States, a common speed limit is 70 m.p.h., and in some places it is 75 m.p.h.).
- +65 is the code for international direct dial telephone calls to Singapore.
- as an age, 65 years old is
- CVN-65 is the designation of the U.S. Navy's first nuclear-powered aircraft carrier, the USS Enterprise (CVN-65).
- 65 is the minimum grade or average required to pass an exam, or a class, in some schools.
- The setting of the American classic TV series Naked City (1958–63) was the 65th Precinct in New York City (sometimes referred to as simply "the 65").
- 65 The number of the French department Hautes-Pyrénées.
- 65 is commonly used in names of many dishes of South India cuisine, for instance Chicken 65.
- The M-65 field jacket was commonly worn by American troops during the War in Vietnam.
- A 65th anniversary is sometimes referred to as a sapphire jubilee.
- The AGM-65 Maverick is a mass-produced air-to-ground tactical missile (AGM) designed for close air support against a wide range of targets.
- Sloane, N. J. A. (ed.). "Sequence A001358". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- "Sloane's A000567 : Octagonal numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
- "Sloane's A002064 : Cullen numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
- "Sloane's A028442 : Numbers n such that Mertens' function is zero". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
- Sloane, N. J. A. (ed.). "Sequence A006003". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- "Sloane's A000931 : Padovan sequence". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.