74 (number) explained

Number:	74
Divisor:	1, 2, 37, 74

74 (seventy-four) is the natural number following 73 and preceding 75.

In mathematics

74 is:

• the twenty-first distinct semiprime^[1] and the eleventh of the form (2.q), where q is a higher prime.
• with an aliquot sum of 40, within an aliquot sequence of three composite numbers (74,40,50,43,1,0) to the Prime in the 43-aliquot tree.
• a palindromic number in bases 6 (202₆) and 36 (22₃₆).
• a nontotient.^[2]
• the number of collections of subsets of that are closed under union and intersection.
• φ(74) = φ(σ(74)).^[3]

There are 74 different non-Hamiltonian polyhedra with a minimum number of vertices.^[4]

In science

• The atomic number of tungsten

In astronomy

• Messier object M74, a magnitude 10.5 spiral galaxy in the constellation Pisces.
• The New General Catalogue object NGC 74, a galaxy in the constellation Andromeda.

In music

• Seventy-four, one of the Number Pieces by John Cage
• "Seventy-Four", a song by the American band Bright from the album The Albatross Guest House

In other fields

See also: List of highways numbered 74. Seventy-four is also:

• The year AD 74, 74 BC, or 1974
• Designates the 7400 series of Integrated Chips. 74xx xx=00-4538
• A seventy-four was a third-rate warship with 74 guns.
• The registry of the U.S. Navy's nuclear aircraft carrier USS John C. Stennis (CVN-74), named after U.S. Senator John C. Stennis
• A hurricane or typhoon is a system with sustained winds of at least 74 mph (64 knots).
• The number of the French department Haute-Savoie
• In the Bible it is the number of people that were in the presence of God on Mount Sinai and saw God without dying "Exodus 24:9-11"

Notes and References

1. A001358.
2. Web site: Sloane's A005277 : Nontotients. The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. 2016-05-29.
3. phi(sigma(k)).
4. Web site: Sloane's A007033: Non-Hamiltonian polyhedra with n nodes.. The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. 2020-12-11.