6213
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 8800
- Proper Divisor Sum (Aliquot Sum)
- 2587
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 3888
- Möbius Function
- -1
- Radical
- 6213
- 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
- 124
- 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
- Expansion of x^3*(5-2*x)*(1-x^3)/(1-x)^4.at n=36A000338
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 52.at n=23A031550
- a(n)=(s(n)+4)/10, where s(n)=n-th base 10 palindrome that starts with 6.at n=43A043085
- a(n) is the first of a triple of consecutive integers, each of which is the product of three distinct primes.at n=7A066509
- Positions of A080268 in A014486.at n=3A080270
- Poincaré series [or Poincare series] (or Molien series) for a certain five-fold wreath product P_5.at n=36A091726
- Position of A051912 in A093110. a(n) is the number of integers < A051912(n) that can be expressed as a sum of three terms from A051912.at n=34A093111
- Triangle T, read by rows, such that the matrix cube shifts T one place diagonally left and upward, with T(n, 0) = T(n, n) = 1 for n>=0.at n=70A096744
- E.g.f.: (3-log(1-2*x))/(1-2*x)^(1/2).at n=5A114161
- Sums of p-th to the q-th prime where p and q are twin primes.at n=19A114379
- a(1)=4; a(n) = floor((31+Sum_{i=1..n-1} a(i))/7).at n=55A120189
- Least common multiple of 3 and n^2+n+1.at n=45A130723
- a(n) is the n-th J_17-prime (Josephus_17 prime).at n=11A163797
- A sequence of triples of squarefree consecutive integers each composed of exactly three primes.at n=21A165936
- Numbers k that divide the sum of digits of 21^k.at n=46A175589
- Number of transpose partition pairs of order n whose number of odd parts differ by numbers of the form 4*k + 2.at n=40A190101
- Number of ways to arrange 4 nonattacking triangular rooks on an nXnXn triangular grid.at n=8A193982
- T(n,k) is the number of ways to arrange k nonattacking triangular rooks on an nXnXn triangular grid.at n=74A193986
- Triangle of coefficients of polynomials u(n,x) jointly generated with A209418; see the Formula section.at n=63A209417
- a(n) = (3*2^(n+2) + n*(n+5))/2 - 6.at n=10A239745