6726
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 14400
- Proper Divisor Sum (Aliquot Sum)
- 7674
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2088
- Möbius Function
- 1
- Radical
- 6726
- 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
- 44
- 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
- Companion Pell numbers: a(n) = 2*a(n-1) + a(n-2), a(0) = a(1) = 2.at n=10A002203
- a(n) = 6*a(n-1) - a(n-2), with a(0) = 2, a(1) = 6.at n=5A003499
- a(n) is the number of forests with n (unlabeled) nodes in which each component tree is planted, that is, is a rooted tree in which the root has degree 1.at n=12A005198
- Number of points on surface of octahedron; also coordination sequence for cubic lattice: a(0) = 1; for n > 0, a(n) = 4n^2 + 2.at n=41A005899
- Number of corners, or planar partitions of n with only one row and one column.at n=18A006330
- a(n) = floor( n*(n-1)*(n-2)/29 ).at n=59A011911
- Expansion of 1/(1-x^7-x^8-x^9-x^10-x^11-x^12-x^13-x^14-x^15).at n=52A017864
- a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n-k+1), where k = floor( n/2 ), s = natural numbers >= 3.at n=37A024875
- Character of extremal vertex operator algebra of rank 19.at n=3A028543
- 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 82.at n=0A031580
- Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 82.at n=1A031760
- Numerators of continued fraction convergents to sqrt(32).at n=9A041052
- Denominators of continued fraction convergents to sqrt(210).at n=5A041391
- Table by antidiagonals where T(n,k) = n*T(n,k-1) - T(n,k-2) with T(n,0) = 2 and T(n,1) = n.at n=72A060964
- Numbers k such that the period of the continued fraction for sqrt(2)*k (A064848) is 2.at n=37A065029
- Indices of spheres mentioned in A071609.at n=45A076180
- Numbers n such that |real(zeta(1/2 + n*I))| exceeds all previous values, where zeta is the Riemann zeta function.at n=18A079630
- Non-palindromic numbers n such that phi(n) = phi(reversal(n)).at n=8A097647
- Expansion of (1+x^2)/(1-2*x-x^2).at n=10A099425
- A number triangle associated with the Chebyshev polynomials of the first kind.at n=49A101161