43
domain: N
Properties
Digital Properties
- Digit Count
- 2
- Digit Sum
- 7
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 44
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 42
- Möbius Function
- -1
- Radical
- 43
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- no
- Lucas Number
- no
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 29
- Smith Number
- no
Classification
- Natural
- yes
- Even
- no
- Odd
- yes
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- yes
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 14
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Names
- German
- dreiundvierzig· ordinal: dreiundvierzigste
- English
- forty-three· ordinal: forty-third
- Spanish
- cuarenta y tres· ordinal: 43º
- French
- quarante-trois· ordinal: quarante-troisième
- Italian
- quarantatre· ordinal: 43º
- Latin
- quadraginta tres· ordinal: 43.
- Portuguese
- quarenta e três· ordinal: 43º
Appears in sequences
- Number of ways of making change for n cents using coins of 1, 2, 5, 10 cents.at n=21A000008
- Smallest prime power >= n.at n=41A000015
- Smallest prime power >= n.at n=42A000015
- Mosaic numbers or multiplicative projection of n: if n = Product (p_j^k_j) then a(n) = Product (p_j * k_j).at n=42A000026
- The positive integers. Also called the natural numbers, the whole numbers or the counting numbers, but these terms are ambiguous.at n=42A000027
- Let k = p_1^e_1 p_2^e_2 p_3^e_3 ... be the prime factorization of n. Sequence gives k such that the sum of the numbers of 1's in the binary expansions of e_1, e_2, e_3, ... is odd.at n=21A000028
- Numbers that are not squares (or, the nonsquares).at n=36A000037
- 1-digit numbers arranged in alphabetical order, then the 2-digit numbers arranged in alphabetical order, then the 3-digit numbers, etc.at n=41A000052
- Primes that divide at least one term in every Fibonacci sequence.at n=4A000057
- Sylvester's sequence: a(n+1) = a(n)^2 - a(n) + 1, with a(0) = 2.at n=3A000058
- A Beatty sequence: a(n) = floor(n/(e-2)).at n=30A000062
- Number of odd integers <= 2^n of form x^2 + y^2.at n=7A000074
- Number of integers <= 2^n of form 4 x^2 + 4 x y + 5 y^2.at n=8A000076
- Positive zeros of Bessel function of order 0 rounded to nearest integer.at n=13A000134
- Lower Wythoff sequence (a Beatty sequence): a(n) = floor(n*phi), where phi = (1+sqrt(5))/2 = A001622.at n=26A000201
- a(8i+j) = 13i + a(j), where 1<=j<=8.at n=26A000202
- Remove all factors of 2 from n; or largest odd divisor of n; or odd part of n.at n=42A000265
- 3*n - 2*floor(sqrt(4*n+5)) + 5.at n=18A000277
- Sums of three squares: numbers of the form x^2 + y^2 + z^2.at n=37A000378
- Numbers of form x^2 + y^2 + 7z^2.at n=34A000394