12897
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 27
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 18642
- Proper Divisor Sum (Aliquot Sum)
- 5745
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8592
- Möbius Function
- 0
- Radical
- 4299
- Omega Function (Ω)
- 3
- 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
- 63
- 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
- no
- Odd
- yes
Appears in sequences
- Numbers k such that the continued fraction for sqrt(k) has period 96.at n=35A020435
- a(n) = Sum{T(i,j)}, 0<=j<=i, 0<=i<=n, T given by A026568.at n=10A026582
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 58 ones.at n=23A031826
- a(n) = (10*n^3 - 9*n^2 + 2*n)/3 + 1.at n=16A034721
- Consider problem of placing N queens on an n X n board so that each queen attacks precisely k others. Here k=1 and sequence gives number of inequivalent solutions when N is equal to the upper bound 2*floor(2n/3).at n=7A051567
- Consider problem of placing A051754(n) queens on an n X n board so that each queen attacks precisely 1 other. Sequence gives number of solutions up to square symmetry.at n=8A051757
- Number of partitions of n which represent first player winning Chomp positions with unique winning moves.at n=37A112472
- a(n) = 8 + floor((2 + Sum_{j=1..n-1} a(j))/4).at n=33A120166
- Number of compositions of n in which the maximal multiplicity of parts equals 2.at n=17A243119
- Triangle read by rows: T(n, k) = C(n, k)*C(2*k, k)/(k+1) - sum(j = 0..k, (-1)^j*(1-j)^n*C(k, j)/k!), 0<=k<=n.at n=53A247493
- Number of active (ON, black) cells at stage 2^n-1 of the two-dimensional cellular automaton defined by "Rule 627", based on the 5-celled von Neumann neighborhood.at n=6A273275
- Number of integer partitions of n of even rank.at n=38A340601
- Numbers that are the sum of seven fifth powers in two or more ways.at n=18A345605
- Numbers that are the sum of seven fifth powers in exactly two ways.at n=18A346279
- Odd numbers for which sigma(k) is congruent to 2 modulo 4 and the 3-adic valuation of k is one larger than the 3-adic valuation of sigma(k).at n=46A351534
- Number of edges in an equilateral triangle when n internal equilateral triangles are drawn between the 3n points that divide each side into n+1 equal parts.at n=47A357008
- Number of Grassmannian permutations of size n that avoid a pattern, sigma, where sigma is a pattern of size 9 with exactly one descent.at n=14A362196
- a(n) = (1/phi(n)) * Sum_{j=1..n} Sum_{k=1..n} phi(n*j*k).at n=15A372668