16813
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 19008
- Proper Divisor Sum (Aliquot Sum)
- 2195
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 14784
- Möbius Function
- -1
- Radical
- 16813
- Omega Function (Ω)
- 3
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 66
- 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
- no
- Odd
- yes
Appears in sequences
- Erroneous version of A024368.at n=17A025068
- Numbers whose base-7 representation contains exactly four 0's.at n=11A043396
- Numbers k such that 1000000000k+1, 1000000000k+3, 1000000000k+7, 1000000000k+9 are all primes.at n=1A064968
- a(n) = 2*a(n-2)+5*a(n-3), n>6.at n=16A107229
- a(0)=1, a(1)=1, a(n)=7*a(n/2) for n=2,4,6,..., a(n)=6*a((n-1)/2)+a((n+1)/2) for n=3,5,7,....at n=33A116522
- Number of necklaces of n beads with up to n colors, with cyclic permutation {1,..,n} of the colors taken to be equivalent.at n=6A130293
- Number of lower triangles of a 4 X 4 0..n array with each element differing from all of its diagonal, vertical, antidiagonal and horizontal neighbors by one or less.at n=7A195234
- Number of nX3 0..2 arrays with no occurrence of three equal elements in a row horizontally, vertically, diagonally or antidiagonally, and new values 0..2 introduced in row major order.at n=3A204973
- Number of nX4 0..2 arrays with no occurrence of three equal elements in a row horizontally, vertically, diagonally or antidiagonally, and new values 0..2 introduced in row major order.at n=2A204974
- T(n,k)=Number of nXk 0..2 arrays with no occurrence of three equal elements in a row horizontally, vertically, diagonally or antidiagonally, and new values 0..2 introduced in row major order.at n=17A204978
- T(n,k)=Number of nXk 0..2 arrays with no occurrence of three equal elements in a row horizontally, vertically, diagonally or antidiagonally, and new values 0..2 introduced in row major order.at n=18A204978
- Fibonacci sequence beginning 13, 9.at n=16A206609
- Number of (w,x,y) with all terms in {0,...,n} and w<=x+y and x<=y.at n=33A212983
- G.f. A(x) satisfies: A(x)^8 = A(x^2)^4 + 8*x.at n=7A223026
- Numbers of the form 6^j + 7^k, for j and k >= 0.at n=31A226819
- Least integer m > 0 such that pi(m*n) divides prime(m) + prime(n), where pi(x) denotes the number of primes not exceeding x.at n=45A247793
- a(n) = 7^n + 6.at n=5A253210
- a(n) = n^5 + n - 1.at n=7A271208
- Number of permutations of [n] avoiding {4231, 1324, 2341}.at n=10A294801
- a(n) is the number of vertices in the diagram of partitions of n (see example).at n=30A299475