4191
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 6144
- Proper Divisor Sum (Aliquot Sum)
- 1953
- 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
- 2520
- Möbius Function
- -1
- Radical
- 4191
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
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
- 108
- Smith Number
- yes
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Number of graphs with n nodes and n-2 edges.at n=11A001430
- a(n) = T(2n-1,n), where T is the array in A026098.at n=30A026102
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 21.at n=25A031519
- Coordination sequence T2 for Zeolite Code AFN.at n=46A038402
- Coordination sequence T4 for Zeolite Code STT.at n=43A038417
- Ruth-Aaron numbers (2): sum of prime divisors of n = sum of prime divisors of n+1 (both taken with multiplicity).at n=13A039752
- Numbers having three 6's in base 9.at n=5A043479
- Numbers whose base-8 representation has exactly 5 runs.at n=20A043627
- Numbers m such that string 9,1 occurs in the base 10 representation of m but not of m+1.at n=45A044804
- A simple context-free grammar: convolution cube of A001002.at n=9A052703
- G.f. A(x) satisfies: A(x) = exp( Sum_{k>=1} A(x^k)^5 * x^k / k ).at n=5A052781
- Number of positive integers <= 2^n of form 3 x^2 + 5 y^2.at n=15A054162
- Number of positive integers <= 2^n of form x^2 + 15 y^2.at n=15A054229
- First (leftmost) digit - second digit + third digit - fourth digit .... = 11.at n=44A061880
- Numbers k such that sopf(k) = sopfr(k+1), where sopf(k) = A008472(k) and sopfr(k) = A001414(k).at n=12A064678
- Numbers k such that sigma(2k + 2) = 4k.at n=6A067680
- Expansion of (1 + x)*(1 - x + x^2)/((1 - x)^4*(1 + x + x^2)).at n=32A070333
- a(n) = smallest multiple of prime(n) such that a(n) +1 is a multiple of prime(n+1).at n=30A077338
- Expansion of (1 - x - x^2 - sqrt(1 - 2*x - 5*x^2 - 2*x^3 + x^4)) / (2*x + 2*x^2).at n=10A078481
- A014486-indices of symmetric binary trees.at n=11A083940