6780
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
- 1
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 19152
- Proper Divisor Sum (Aliquot Sum)
- 12372
- 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
- 1792
- Möbius Function
- 0
- Radical
- 3390
- Omega Function (Ω)
- 5
- 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
- 181
- 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
- Numbers with exactly five distinct base-9 digits.at n=15A031986
- Coefficients of cluster series for site percolation problem on triangular lattice with 1st and 2nd neighbor bonds.at n=5A036392
- Denominators of continued fraction convergents to sqrt(227).at n=3A041423
- Number of homeomorphically irreducible multigraphs (or series-reduced multigraphs or multigraphs without nodes of degree 2) on 4 labeled nodes.at n=13A060534
- Numbers k such that phi(x) = k has exactly 7 solutions.at n=41A060670
- Total sum of odd parts in all partitions of n.at n=19A066967
- Numbers k such that k-1, k+1 and k^2+1 are prime numbers.at n=20A070155
- Numbers n such that n and the n-th prime have the same digits.at n=15A074350
- Numbers k such that (k-1, k+1) and (k/2-1, k/2+1) are both pairs of twin primes.at n=7A076504
- Maximal coefficient of the polynomial (1-x)*(1-x^2)*...*(1-x^n).at n=60A086376
- Radius of inscribed circle within primitive Pythagorean triangles having legs that add up to a square, sorted on hypotenuse.at n=25A089551
- Sum of smallest parts (counted with multiplicity) of all partitions of n into odd parts.at n=37A092313
- Let p(k) be the number of partitions of k (A000041); a(n) = Sum_{1<=k<=n, gcd(k,n)=1} p(k).at n=29A096223
- Numbers k such that (273*2^k+1)^2-2 is prime.at n=21A100914
- Fibonacci(p-J(p,5)) mod p^2, where p is the n-th prime and J is the Jacobi symbol.at n=29A113650
- a(n) = 4*n*(floor(n^2/2)+1). For n >= 3, this is the number of directed Hamiltonian paths on the n-prism graph.at n=15A124350
- Start with i=1 and j=2. Concatenate i and j, get k = floor(ij/j), concatenate j and k, etc.at n=17A127320
- Numbers m such that m^4-1 has no divisors d with 1 < d < m-1.at n=21A129293
- Numbers k such that the number of digits d in k^2 is not prime and for each factor f of d the sum of the d/f digit groupings in k^2 of size f is a square.at n=19A153745
- Numbers k such that there are 8 digits in k^2 and for each factor f of 8 (1,2,4) the sum of digit groupings of size f is a square.at n=9A153746