13008
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 20
- Divisor Sum
- 33728
- Proper Divisor Sum (Aliquot Sum)
- 20720
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4320
- Möbius Function
- 0
- Radical
- 1626
- Omega Function (Ω)
- 6
- 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
- no
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 45
- 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+1) = 1 + a( floor(n/1) ) + a( floor(n/2) ) + ... + a( floor(n/n) ).at n=42A003318
- a(n) is the number of compositions of n in which the maximum part size is 5.at n=17A006979
- Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 19.at n=5A031697
- Number of nonisomorphic partitions of n on the Ferrers diagram.at n=38A095814
- a(n) = (Sum_{k=1..n} 1/c(k))*(Product_{j=1..n} c(j)), where c(j) is the j-th composite.at n=4A110957
- Average of twin primes k such that k = p1^3 + p2^2, where p1 and p2 are consecutive primes, and p1 < p2.at n=0A138762
- Average of twin primes p4 = p1^3 + p2^2 such that p1 < p2 are consecutive primes and p3 = p1^2 + p2^3 is also an average of twin primes.at n=0A139777
- 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, -1, 1), (-1, 1, 1), (0, 0, -1), (0, 1, 1), (1, 0, -1)}.at n=9A148727
- a(n) = 361*n^2 + 2*n.at n=5A158309
- Consider the base-7 Kaprekar map n->K(n) defined in A165071. Sequence gives numbers belonging to cycles, including fixed points.at n=8A165076
- Consider the base-7 Kaprekar map n->K(n) defined in A165071. Sequence gives numbers belonging to cycles of length greater than 1.at n=7A165078
- Triangle of coefficients of polynomials v(n,x) jointly generated with A208932; see the Formula section.at n=48A208932
- Number of length 1+2 0..n arrays with no three consecutive terms having the sum of any two elements equal to twice the third.at n=22A248462
- Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000000 or 00000001.at n=10A259635
- Non-repdigit numbers k that divide A045876(k).at n=7A276413
- Average of twin prime pairs that is a product of two averages of twin prime pairs.at n=31A307758
- Number of polygons formed outside an n X n square when connecting all 4n points on the perimeter of the square by infinite lines.at n=7A345648
- Members of A014574 with sum of prime factors (with multiplicity) also in A014574.at n=15A349455
- Numbers m such that the smallest digit in the decimal expansion of 1/m is 5, ignoring leading and trailing 0's.at n=11A352159
- Number of fixed triangular n-ominoes of the regular tiling with Schläfli symbol {3,6} that have a common axis of symmetry coincident with cell altitudes and the point of the polyomino farthest along that axis in a specified direction is a cell vertex.at n=21A364486