6189
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 8256
- Proper Divisor Sum (Aliquot Sum)
- 2067
- 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
- 4124
- Möbius Function
- 1
- Radical
- 6189
- 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
- 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
- 36
- 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
- Number of compositions of n such that no two adjacent parts are equal (these are sometimes called Carlitz compositions).at n=17A003242
- Expansion of e.g.f.: exp(log(1+x)*cosh(x)).at n=9A009193
- "Pascal sweep" for k=10: draw a horizontal line through the 1 at C(k,0) in Pascal's triangle; rotate this line and record the sum of the numbers on it (excluding the initial 1).at n=44A009550
- a(n) = floor( n*(n-1)*(n-2)/19 ).at n=50A011901
- A015938(n)-2^n.at n=40A015939
- 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 52.at n=22A031550
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 40 ones.at n=25A031808
- Numbers k such that 95*2^k+1 is prime.at n=25A032397
- Numbers whose base-5 representation contains exactly two 2's and three 4's.at n=17A045288
- a(1) = 5; a(n) is smallest number > a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.at n=41A074340
- Trajectory of 77 under the Reverse and Add! operation carried out in base 2.at n=10A075253
- Convolution of A075298 with A056594.at n=29A075495
- In base 4, smallest number that requires n Reverse and Add! steps to reach a palindrome.at n=24A077441
- Triangle read by rows: T(n,k) is the number of peakless Motzkin paths of length n containing k subwords of the type U H^j U or D H^j D for some j>0, where U=(1,1), H=(1,0) and D=(1,-1) (can be easily expressed using RNA secondary structure terminology).at n=42A097100
- Inverse Moebius transform of 5-simplex numbers A000389.at n=12A101289
- Semiprimes that are semiprimes turned upside-down.at n=37A119738
- Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 110-111-110 pattern in any orientation.at n=13A146270
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, 0, 0), (0, -1, 0), (0, 0, 1), (1, 1, 0), (1, 1, 1)}.at n=6A151229
- Number of peakless Motzkin paths of length n containing no subwords of type uh^ju or dh^jd (j>=1), where u=(1,1), h=(1,0), and d=(1,-1) (can be easily expressed using RNA secondary structure terminology).at n=15A190160
- Numbers k such that sigma(tau(phi(k))) = phi(tau(sigma(k))).at n=29A226118