44 (number)
| ||||
---|---|---|---|---|
Cardinal | forty-four | |||
Ordinal | 44th (forty-fourth) | |||
Factorization | 22 × 11 | |||
Divisors | 1, 2, 4, 11, 22, 44 | |||
Greek numeral | ΜΔ´ | |||
Roman numeral | XLIV, xliv | |||
Binary | 1011002 | |||
Ternary | 11223 | |||
Senary | 1126 | |||
Octal | 548 | |||
Duodecimal | 3812 | |||
Hexadecimal | 2C16 |
44 (forty-four) is the natural number following 43 and preceding 45.
In mathematics
[edit]Forty-four is a repdigit and palindromic number in decimal. It is the tenth 10-happy number,[1] and the fourth octahedral number.[2]
It is a square-prime of the form p2 × q, and fourth of this form and of the form 22 × q, where q is a higher prime.
It is the first member of the first cluster of two square-primes; of the form p2 × q, specifically 22 × 11 = 44 and 32 × 5 = 45. The next such cluster of two square-primes comprises 22 × 29 = 116, and 32 × 13 = 117.
44 has an aliquot sum of 40, within an aliquot sequence of three composite numbers (44, 40, 50, 43, 1, 0) rooted in the prime 43-aliquot tree.
Since the greatest prime factor of 442 + 1 = 1937 is 149 and thus more than 44 twice, 44 is a Størmer number.[3] Given Euler's totient function, φ(44) = 20 and φ(69) = 44.
44 is a tribonacci number, preceded by 7, 13, and 24, whose sum it equals.[4]
44 is the number of derangements of 5 items.[5]
There are only 44 kinds of Schwarz triangles, aside from the infinite dihedral family of triangles (p 2 2) with p = {2, 3, 4, ...}.[6]
There are 44 distinct stellations of the truncated cube and truncated octahedron, per Miller's rules.[7]
44 four-dimensional crystallographic point groups of a total 227 contain dual enantiomorphs, or mirror images.[8]
There are forty-four classes of finite simple groups that arise from four general families of such groups:
- Two general groups stem from cyclic groups and alternating groups.
- Sixteen families of groups stem from simple groups of Lie type.
- Twenty-six groups are sporadic.
Sometimes the Tits group is considered a 17th non-strict simple group of Lie type, or a 27th sporadic group, which would yield a total of 45 classes of finite simple groups.
In other fields
[edit]Forty-four is:
- Mark Twain's The Mysterious Stranger features Satan's supposed nephew, whose alternate name in parallel works is "44".
- A song by The Residents. In "44", included in The Resident's Live at the Fillmore album, the number 44 is a main focus.
References
[edit]- ^ "Sloane's A007770 : Happy numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
- ^ "Sloane's A005900 : Octahedral numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
- ^ "Sloane's A005528 : Størmer numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
- ^ "Sloane's A000073 : Tribonacci numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
- ^ "Sloane's A000166 : Subfactorial or rencontres numbers, or derangements". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-30.
- ^ Messer, Peter W. (2002). "Closed-Form Expressions for Uniform Polyhedra and Their Duals" (PDF). Discrete & Computational Geometry. 27 (3). Springer: 353–355, 372–373. doi:10.1007/s00454-001-0078-2. MR 1921559. S2CID 206996937. Zbl 1003.52006.
- ^ Webb, Robert. "Enumeration of Stellations". www.software3d.com. Archived from the original on 2022-11-26. Retrieved 2022-11-25.
- ^ Souvignier, Bernd (2003). "Enantiomorphism of crystallographic groups in higher dimensions with results in dimensions up to 6". Acta Crystallographica Section A. 59 (3): 217. doi:10.1107/s0108767303004161. PMID 12714771. S2CID 26198482. Zbl 1370.20045.