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==In mathematics== |
==In mathematics== |
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'''Seventy-two''' is the sum of four consecutive [[prime number|primes]] (13 + 17 + 19 + 23), as well as the sum of six consecutive primes (5 + 7 + 11 + 13 + 17 + 19). The product of 8 and 9, 72 is a [[pronic number]]. And as a multiple of a perfect number, 72 is itself a [[semiperfect number]]. |
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The sum of [[Euler's totient function]] φ(''x'') over the first fifteen integers is 72. There are 17 solutions to the equation φ(''x'') = 72, more than any integer below 72, making it a [[highly totient number]]. |
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==In science== |
==In science== |
Revision as of 23:35, 27 June 2008
72 (seventy-two) is the natural number following 71 and preceding 73. It is half a gross or 6 dozen (i.e., 60 in duodecimal).
Template:Numbers 70s | |
Cardinal | 72 seventy-two |
Ordinal | 72nd seventy-second |
Factorization | |
Divisors | 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72 |
Roman numeral | LXXII |
Binary | 1001000 |
Duodecimal | 60 |
Hexadecimal | 48 |
In mathematics
Seventy-two is the sum of four consecutive primes (13 + 17 + 19 + 23), as well as the sum of six consecutive primes (5 + 7 + 11 + 13 + 17 + 19). The product of 8 and 9, 72 is a pronic number. And as a multiple of a perfect number, 72 is itself a semiperfect number.
The sum of Euler's totient function φ(x) over the first fifteen integers is 72. There are 17 solutions to the equation φ(x) = 72, more than any integer below 72, making it a highly totient number.
72 is the smallest number whose fifth power is the sum of 5 smaller fifth powers; 195 + 435 + 465 + 475 + 675 = 725
The sum of the eighth row of Lozanić's triangle is 72.
In a plane, the exterior angles of a regular pentagon measure 72 degrees each.
In base 10, the number 72 is a Harshad number.
In science
- The atomic number of hafnium
- In degrees Fahrenheit considered to be room temperature.
- The average number of heartbeats per minute for a resting adult.
In astronomy
- Messier object M72, a magnitude 10.0 globular cluster in the constellation Aquarius.
- The New General Catalogue object NGC 72, a magnitude 13.5 barred spiral galaxy in the constellation Andromeda.
- The Saros number of the solar eclipse series which began on -727 August 16 and ended on 752 January 21. The duration of Saros series 72 was 1478.1 years, and it contained 83 solar eclipses.
- The Saros number of the lunar eclipse series which began on -407 June 5 and ended on 891 July 25. The duration of Saros series 72 was 1298.1 years, and it contained 73 lunar eclipses.
In religion
- The conventional number of scholars translating the Septuagint, according to the legendary account in the "Letter of Aristeas".
- The conventional number of disciples sent forth by Jesus in Luke 10 in some manuscripts (seventy in others).
- The number of names of God, according to Kabbalah (see names of God in Judaism).
- The Shemhamphorasch related to the number of the names of God.
- The total number of books in the Holy Bible in the Catholic version if the Book of Lamentations is considered part of the Book of Jeremiah.
- The number of warriors on the Muslim side at the Battle of Badr.
- The number of people martyred along with Imam Hussain at the Battle of Karbala.
- The number of soldiers who will fight alongside Imam Mahdi against the Dajjal, according to Islamic ahadith.
- The number of virgins a Muslim might get as a reward in Heaven, according to some critics of Islam.
- The number of devils according to The Lesser Key of Solomon.
In other fields
Seventy-two is also:
- The ASCII code for 'H'
- The number of hours in 3 days.
- In dpi, the standard resolution of an Apple Macintosh screen.
- The number of the French department Sarthe.
- The designation of USA Interstate 72, a freeway that runs from Missouri to Illinois, East <> West.
- The registry of the U.S. Navy's nuclear aircraft carrier USS Abraham Lincoln (CVN-72), named after U.S. President Abraham Lincoln.
- The designation of the Soviet T-72 tank.
- In the movie The Red Violin, the lot number of the Bussotti red violin at the DuVal auction house.
- The year AD 72, 72 BC, 1972, or any other year ending with "72".
- The Rule of 72 in finance.
- A loud tone of 72Hz makes light objects vibrate.
- Book: 72 Hour Hold by Bebe Moore Campbell
- CD: Seventy Two & Sunny by Uncle Kracker
- Jill Clayburgh and LeVar Burton starred in Firestorm: 72 Hours in Oakland (1993)
- Alternative music band The Delta 72
- New York's Dakota Apartments and Strawberry Fields are by 72nd St. and Central Park West
In sports and games
- The usual par for an 18 hole golf course, especially those in tournament play.
- The number of victories the Chicago Bulls got in the 1995-96 NBA season, which is the NBA record.
- Heavyweight boxer Joe Louis fought 72 fights (69-3)
- While playing for the Chicago White Sox, Carlton Fisk wore #72. This was the inverse of the 27 he wore with the Boston Red Sox since that number was not available when he arrived in Chicago.
- Former NFL defensive tackle William Perry, most famously of the 1985 Chicago Bears, wore #72.
- King Of The Hill character Bill Daughtreve is often shown wearing #72 during his high school football playing days. The character's high school career shares many of the same elements as Perry's pro career.
- The number of spaces in a game of Parcheesi, from start space to "home."
- The number of tiles in the original base game of the popular Carcassonne (board game).
- The number of Stefan Evers, 10 fold world champion motor cross