4181
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 4332
- Proper Divisor Sum (Aliquot Sum)
- 151
- 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
- 4032
- Möbius Function
- 1
- Radical
- 4181
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- yes
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 33
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- a(n) = 3*a(n-1) - a(n-2) for n >= 2, with a(0) = a(1) = 1.at n=10A001519
- Markoff (or Markov) numbers: union of positive integers x, y, z satisfying x^2 + y^2 + z^2 = 3*x*y*z.at n=16A002559
- Numbers that are the sum of 3 positive 5th powers.at n=27A003348
- Number of perfect matchings (or domino tilings) in K_5 X P_2n.at n=1A003747
- Fully multiplicative with a(prime(k)) = Fibonacci(k+2).at n=58A003965
- Numbers that are the sum of at most 3 positive 5th powers.at n=47A004843
- a(n) = floor(n*phi^10), where phi is the golden ratio, A001622.at n=34A004925
- a(n) = 3*a(n-2) - a(n-4), a(0)=2, a(1)=1, a(2)=3, a(3)=2. Alternates Lucas (A000032) and Fibonacci (A000045) sequences for even and odd n.at n=19A005247
- Bruckman-Lucas pseudoprimes: k | (L_k - 1), where k is composite and L_k = Lucas numbers A000032.at n=4A005845
- Duplicate of A001519.at n=10A011783
- Odd Fibonacci numbers.at n=12A014437
- Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite BEA = Beta Na7[Al7Si57O128] starting with a T1 atom.at n=11A019067
- Smallest Fibonacci number beginning with n.at n=4A020345
- Numbers k such that the continued fraction for sqrt(k) has period 35.at n=11A020374
- Pisot sequence E(2,3).at n=16A020695
- Pisot sequences E(3,5), P(3,5).at n=15A020701
- Pisot sequences E(5,8), P(5,8).at n=14A020712
- a(n) = s(1)*t(n) + s(2)*t(n-1) + ... + s(k)*t(n+1-k), where k = floor((n+1)/2), s = (Fibonacci numbers), t = A023533.at n=52A024466
- a(n) = s(1)*t(n) + s(2)*t(n-1) + ... + s(k)*t(n+1-k), where k = floor((n+1)/2), s = (F(2), F(3), ...), t = A023533.at n=51A024595
- a(n) = s(1)*t(n) + s(2)*t(n-1) + ... + s(k)*t(n-k+1), where k = floor(n/2), s = A000045, t = A023533.at n=51A025086