43 (number)

← 42 43 44 →
← 40 41 42 43 44 45 46 47 48 49 → List of numbers Integers ← 0 10 20 30 40 50 60 70 80 90 →
Cardinal	forty-three
Ordinal	43rd (forty-third)
Factorization	prime
Prime	14th
Divisors	1, 43
Greek numeral	ΜΓ´
Roman numeral	XLIII, xliii
Binary	1010112
Ternary	11213
Senary	1116
Octal	538
Duodecimal	3712
Hexadecimal	2B16

43 (forty-three) is the natural number following 42 and preceding 44.

Mathematics

43 is a prime number, and a twin prime of 41. 43 is the smallest prime that is not a Chen prime. 43 is also a Wagstaff prime, ^[1] and a Heegner number. ^[2] 43 is the fourth term of Sylvester's sequence. ^[3]

43 is the largest prime which divides the order of the Janko group J₄.

Dutch mathematician Hendrik Lenstra wrote a mathematical research paper discussing the properties of the number, titled Ode to the number 43.

The Sri Yantra, with nine interlocking triangles that collectively form 43 smaller triangles

Notes

1. Sloane, N. J. A. (ed.). "SequenceA000979(Wagstaff primes)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation. Retrieved 2016-05-30.
2. Sloane, N. J. A. (ed.). "SequenceA003173(Heegner numbers)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation. Retrieved 2016-05-30.
3. Sloane, N. J. A. (ed.). "SequenceA000058(Sylvester's sequence)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation. Retrieved 2016-05-30.

Further reading

Lenstra, Hendrik (2009). Ode to the number 43 (In Dutch). Nieuw Arch. Wiskd. Amsterdam, NL: Koninklijk Wiskundig Genootschap (5) 10, No. 4: 240-244. MR 2590266 Zbl   1263.00002