13842
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 30030
- Proper Divisor Sum (Aliquot Sum)
- 16188
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4608
- Möbius Function
- 0
- Radical
- 4614
- Omega Function (Ω)
- 4
- 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
- yes
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 76
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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
- yes
- Odd
- no
Appears in sequences
- Consider the trajectory of n under the iteration of a map which sends x to 3x - sigma(x) if this is >= 0; otherwise the iteration stops. The sequence gives values of n which eventually reach 0.at n=27A037159
- a(n+1) = a(n) converted to base 10 from base 12.at n=27A055983
- a(n) = A078217(n)/n.at n=8A078811
- a(n) = n^3 plus sum of digits of n^3.at n=23A123135
- Numbers n that raised to the powers from 1 to k (with k>=1) are multiple of the sum of their digits (n raised to k+1 must not be a multiple). Case k=8.at n=23A135193
- Smallest number m such that sigma(m) has exactly n distinct prime factors.at n=5A152562
- Smallest number m such that sigma(m) = A002110(n) where A002110(n) is the product of the first n primes.at n=4A153076
- Number of binary strings of length n with no substrings equal to 0001 or 1010.at n=13A164399
- Arises in covering a graph by forests and a matching.at n=16A179259
- Number of (w,x,y,z) with all terms in {1,...,n} and 3w = x + y + z + n + 1.at n=37A212251
- Rectangular array: (row n) = b**c, where b(h) = -1 + 2^h, c(h) = b(n-1+h), n>=1, h>=1, and ** = convolution.at n=47A213747
- Numbers k such that phi(k-6) = phi(k) = phi(k+6).at n=18A217006
- Smallest sets of 6 consecutive abundant numbers in arithmetic progression. The initial abundant number is listed.at n=30A228963
- Smallest sets of 7 consecutive abundant numbers in arithmetic progression. The initial abundant number is listed.at n=4A228964
- Smallest number k such that sopf(k)/digsum(k) = prime(n) where sopf(k) is the sum of the distinct primes dividing k and digsum(k) the sum of digits of k.at n=13A241049
- p-INVERT of (1,0,0,1,0,0,1,0,0,...), where p(S) = (1 - S)^2.at n=20A289919
- G.f. A(x) satisfies: A(x) = x + x^2 * exp(A(x) - A(-x^2)/2 + A(x^3)/3 - A(-x^4)/4 + ...).at n=17A345234
- Number of edges in a hexagon when n internal hexagons are drawn between the 6n points that divide each side into n+1 equal parts.at n=34A357198
- Number of equivalence classes of lattice polygons contained in a square of side length n but not in a square of side length n-1.at n=4A374975
- a(n) = Sum_{k=0..n} binomial(2*n+2,k) * binomial(2*n-k,n-k).at n=5A386843