72 (number)

72 (seventy-two) is the natural number following 71 and preceding 73. It is half a gross or 6 dozen (i.e., half a "100" in duodecimal).

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.
The sum of the eighth row of Lozanić's triangle is 72.
In normal space, the exterior angles of an equilateral pentagon measure 72 degrees each.
72 is a Harshad number.
The smallest number whose fifth power is the sum of 5 smaller fifth powers; 19^5 + 43^5 + 46^5 + 47^5 + 67^5 = 72^5

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.

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.

Seventy-two is also:

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
Harry Truman received an honorary degree in Civic Law from Oxford University in 1956, at 72

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.
Wisconsin Badgers lineman Joe Thomas wears #72
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.