13817
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 14196
- Proper Divisor Sum (Aliquot Sum)
- 379
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 13440
- Möbius Function
- 1
- Radical
- 13817
- 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
- 120
- 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 walks on cubic lattice.at n=40A005570
- Sum along upward diagonal of Pascal triangle to halfway point.at n=23A010754
- Sum along upward diagonal of Pascal triangle up to (but not including) halfway point.at n=23A010755
- Strong pseudoprimes to base 85.at n=11A020311
- T(n,n-6), array T as in A038738.at n=5A038743
- T(n,n-5), array T as in A038792.at n=18A038795
- Diagonal sums of triangle A099575.at n=21A099577
- One-seventh of the difference of squares of legs of primitive Pythagorean triangles, neither of which is a multiple of 7.at n=43A127924
- Triangle T(n, k, q) = binomial(n, k) - 1 + q^floor(n/2)*binomial(n-2, k-1) with T(n, 0, q) = T(n, n, q) = 1 and q = 3, read by rows.at n=59A173077
- Triangle T(n, k, q) = binomial(n, k) - 1 + q^floor(n/2)*binomial(n-2, k-1) with T(n, 0, q) = T(n, n, q) = 1 and q = 3, read by rows.at n=61A173077
- (A178476(n)-3)/9.at n=6A178486
- Number of n X 2 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 4,2,2,0,2 for x=0,1,2,3,4.at n=9A197642
- Number of binary arrays indicating the locations of trailing edge maxima of a random length-n 0..4 array extended with zeros and convolved with 1,2,1.at n=19A222123
- Decimal representation of the diagonal from the corner to the origin of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 310", based on the 5-celled von Neumann neighborhood.at n=26A287603
- a(n) = 7*n^2 - 7*n - 43.at n=44A298078
- Partial sums of A299254.at n=20A299260
- Numbers k such that 5*10^(2*k) + 5*10^k + 1 is prime.at n=4A309740
- Elliptic Carmichael numbers for the elliptic curve y^2 = x^3 + 80.at n=19A317174
- Expansion of Product_{k>=1} B(x^k), where B(x) is the g.f. of A111374.at n=49A327851
- a(n) = minimal positive k such that the concatenation of decimal digits n and n+1 is a divisor of the concatenation of n+2, n+2+1, ..., n+2+k.at n=29A332830