12782
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
- 3
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 24192
- Proper Divisor Sum (Aliquot Sum)
- 11410
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4920
- Möbius Function
- 1
- Radical
- 12782
- Omega Function (Ω)
- 4
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 76
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = n*(n-1) + (n-2)*(n-3) + ... + 1*0 + 1 for n odd; otherwise, a(n) = n*(n-1) + (n-2)*(n-3) + ... + 2*1.at n=41A014112
- Number of nonempty subsets of {1,2,...,n} in which exactly 1/4 of the elements are <= (n-4)/2.at n=17A048063
- Number of nonempty subsets of {1,2,...,n} in which exactly 1/4 of the elements are <= (n+3)/3.at n=17A048085
- a(n) = Sum_{k=1..n} phi(k)^2.at n=43A057434
- Position of first repeat of the opening sequence of length n occurring after the first repeat of the opening sequence of length n-1 in the Kolakoski sequence (A000002).at n=31A074300
- Indices of triple-safe primes: p=prime(n) is double-safe: q=(p-1)/2, r=(q-1)/2 and s=(r-1)/2 are all prime (and q is double-safe).at n=15A075134
- Number of isomorphism classes of 7-regular multigraphs of order 2n, loops allowed.at n=2A129435
- Number of line segments in regular n-gon with all diagonals drawn.at n=21A135565
- 11 times pentagonal numbers: 11*n*(3n-1)/2.at n=28A153449
- A(n,k) for n >= k in triangular ordering, where A(n,k) is the number of compositions (ordered partitions) of n into k parts, with the first part greater than or equal to all other parts.at n=54A156042
- A(n,n), where A(n,k) is the number of compositions (ordered partitions) of n into k parts (parts of size 0 being allowed), with the first part being greater than or equal to all the rest.at n=9A156043
- a(n) = greatest entry in row n of A184957.at n=19A188624
- Number of (n+2) X 5 0..2 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically, diagonally or antidiagonally exactly three ways, and new values 0..2 introduced in row major order.at n=8A204279
- Number of (w,x,y) with all terms in {0,...,n} and |w-x| < |x-y| < |y-w|.at n=43A212964
- Number of binary arrays indicating the locations of trailing edge maxima of a random length-n 0..7 array extended with zeros and convolved with 1,3,3,1.at n=19A222026
- a(n) = 1*2 + 3*4 + 5*6 + 7*8 + 9*10 + 11*12 + 13*14 + ... + (up to n).at n=41A228958
- a(n) = n*(n + 1)*(4*n - 1)/3.at n=21A268684
- Number of Dyck paths of semilength n such that each level has exactly ten peaks or no peaks.at n=20A288117
- Number of nX6 0..1 arrays with every element equal to 0, 2, 3, 4 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=3A302887
- T(n,k)=Number of nXk 0..1 arrays with every element equal to 0, 2, 3, 4 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=39A302889