13818
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 32832
- Proper Divisor Sum (Aliquot Sum)
- 19014
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 3864
- Möbius Function
- 0
- Radical
- 1974
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 4
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
- 58
- 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
- a(n) = floor( n*(n-1)*(n-2)/8 ).at n=49A011890
- Fibonacci sequence beginning 0, 14.at n=16A022348
- Number of partitions of n into prime power parts (1 included); number of nonisomorphic Abelian subgroups of symmetric group S_n.at n=40A023893
- Number of 3 X n binary matrices with distinct rows, up to row and column permutation; (n,3)-hypergraphs (including empty hyperedge but excluding multiple hyperedges).at n=11A055194
- Numbers k such that 9^k == -1 (mod k-1).at n=5A055692
- Number of (0,1)-strings of length n that avoid the substrings of substrings 11101011 and 101111.at n=14A062259
- a(n) = 100*n^2 - 49*n + 6.at n=11A157651
- (A178476(n)-3)/9.at n=7A178486
- Number of (w,x,y,z) with all terms in {0,...,n} and |w-x|+|x-y+|y-z|=n.at n=24A212904
- Consider coefficients U(m,L,k) defined by the identity Sum_{k=1..L} Sum_{j=0..m} A302971(m,j)/A304042(m,j) * k^j * (T-k)^j = Sum_{k=0..m} (-1)^(m-k) * U(m,L,k) * T^k that holds for all positive integers L,m,T. This sequence gives 4-column table read by rows, where the n-th row lists coefficients U(3,n,k) for k = 0, 1, 2, 3; n >= 1.at n=5A316387
- Expansion of 14*x*(29 + 784*x + 1974*x^2 + 784*x^3 + 29*x^4) / (1 - x)^7.at n=1A317982
- Numbers k such that 355*2^k+1 is prime.at n=14A323002
- a(1)=1, a(n) is the smallest number > a(n-1) such that the simple continued fraction for 1/a(1) + 1/a(2) + ... + 1/a(n) contains exactly n elements.at n=22A354742
- a(n) is the smallest nonnegative integer such that the sum of any nine ordered terms a(k), k<=n (repetitions allowed), is unique.at n=6A365305
- The seventh term of the greedy B_n set of natural numbers.at n=8A369819
- Numbers k such that sigma(k) = psi(k) + tau(k)^2.at n=20A390296
- Nonsquarefree numbers k that are not divisible by p^p for any prime p, and for which A276085(k) is a multiple of A003557(k), where A276085 is the primorial base log-function.at n=50A391866
- Intersection of A391845 and A391866.at n=44A392592