6528
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
- 32
- Divisor Sum
- 18360
- Proper Divisor Sum (Aliquot Sum)
- 11832
- 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
- 2048
- Möbius Function
- 0
- Radical
- 102
- Omega Function (Ω)
- 9
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 31
- 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
- yes
- Odd
- no
Appears in sequences
- Degrees of irreducible representations of Held group He.at n=15A003912
- "Magic" integers: a(n+1) is the smallest integer m such that there is no overlap between the sets {m, m-a(i), m+a(i): 1 <= i <= n} and {a(i), a(i)-a(j), a(i)+a(j): 1 <= j < i <= n}.at n=45A004210
- Number of conjugacy classes in GL(n,3).at n=8A006952
- a(n) = a(n-1) + (3+(-1)^n)*a(n-2)/2.at n=14A007068
- a(n) = 4*a(n-1) - 2*a(n-2) with a(0) = 1, a(1) = 4.at n=7A007070
- Bisection of A001400.at n=46A014125
- Theta series of D*_18 lattice.at n=6A022071
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (Fibonacci numbers), t = (odd natural numbers).at n=21A025083
- Expansion of (theta_3(z)*theta_3(2z)+theta_2(z)*theta_2(2z))^4.at n=26A028579
- 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 39.at n=29A031537
- "DHK[ 5 ]" (bracelet, identity, unlabeled, 5 parts) transform of 1,1,1,1,...at n=30A032246
- Theta series of extremal 3-modular even lattice in dimension 34.at n=3A034627
- Number of points of l_1 norm n in the "diamond" lattice D^+_4.at n=17A035878
- Numbers that are divisible by exactly 9 primes with multiplicity.at n=28A046312
- a(n) = Sum_{i=0..n} T(i,n-i), array T as in A049687.at n=39A049688
- Number of primitive (aperiodic) palindromes using a maximum of three different symbols.at n=14A056459
- Number of primitive (period n) periodic palindromes using a maximum of three different symbols.at n=14A056494
- Numbers k such that sigma(x) = k has exactly 8 solutions.at n=18A060664
- a(0)=0; a(1)=1; a(n) = a(n-1) + (3 + (-1)^n)*a(n-2)/2.at n=16A062112
- Numbers k such that k^2 + 1 is composite and phi(k^2 + 1) == 0 (mod k).at n=21A067519