2143
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 10
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 2144
- 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
- 2142
- Möbius Function
- -1
- Radical
- 2143
- 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
- 169
- Smith Number
- no
- Vampire Number
- no
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
- 324
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Numbers k such that (1,k) is "good".at n=29A000696
- Primes p of the form 3k+1 such that sum_{x=1..p} cos(2*Pi*x^3/p) < -sqrt(p).at n=30A000923
- Number of commutative semigroups of order n.at n=6A001426
- Largest prime == 7 (mod 8) with class number 2n+1.at n=6A002147
- Number of partially achiral trees with n nodes.at n=15A003243
- Number of trivalent planar loopless multigraphs with 2n nodes.at n=6A005966
- Coordination sequence T2 for Zeolite Code LOV.at n=31A008135
- Coordination sequence T1 for Zeolite Code MAZ.at n=32A008144
- a(n) = prime(n^2).at n=17A011757
- Expansion of (1+x^2)/(1 - 2*x - 2*x^2 + x^3).at n=8A014742
- a(n) = 2*a(n-1) + 7*a(n-2), with a(0) = 0, a(1) = 1.at n=7A015519
- Numbers n such that phi(n + 9) | sigma(n) for n not congruent to 0 (mod 3).at n=37A015849
- Numbers k=3*m+1 such that 2^m == 1 (mod k).at n=52A016108
- Numbers k such that the continued fraction for sqrt(k) has period 24.at n=37A020363
- a(n)-th nonsquarefree is sum of first k nonsquarefrees for some k.at n=28A020644
- a(n) = [ a(n-1)/a(1) ] + [ a(n-1)/a(2) ] + ... + [ a(n-1)/a(n-1) ] for n >= 3, with initial terms 1,1.at n=9A022855
- Primes that remain prime through 2 iterations of function f(x) = 2x + 3.at n=37A023242
- Primes that remain prime through 2 iterations of the function f(x) = 5x + 8.at n=24A023255
- Primes that remain prime through 3 iterations of function f(x) = 5x + 8.at n=6A023286
- Coordination sequence T2 for Zeolite Code MWW.at n=31A024987