6807
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
- 4
- Divisor Sum
- 9080
- Proper Divisor Sum (Aliquot Sum)
- 2273
- 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
- 4536
- Möbius Function
- 1
- Radical
- 6807
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 62
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- a(n) = least m such that if r and s in {1/2, 1/4, 1/6, ..., 1/2n} satisfy r < s, then r < k/m < (k+1)/m < s for some integer k.at n=44A024835
- Number of proper factorizations of p1^n*p2^2, where p1 and p2 are distinct primes.at n=19A031125
- 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 54.at n=34A031552
- Numbers k such that 75*2^k-1 is prime.at n=37A050563
- a(n) = 4*n^2 - 6*n + 3.at n=41A054569
- a(n) = floor(product_{k=2..n} log(k)).at n=13A056690
- Sum of the remainders when the n-th triangular number is divided by all smaller triangular numbers > 1.at n=46A072524
- Numbers n such that phi(n) = sigma(sum of distinct prime factors of n).at n=12A075865
- Symmetric secondary structures of RNA molecules with n nucleotides.at n=22A088518
- Antidiagonal sums of table A088925, which lists coefficients T(n,k) of x^n*y^k in f(x,y) that satisfies f(x,y) = 1/(1-x-y) + xy*f(x,y)^3.at n=8A088927
- a(0) = 5, a(1) = 7; for n>1, a(n) = a(n-1)+a(n-2)-(2n-2).at n=19A089061
- Start with 1 and repeatedly reverse the digits and add 35 to get the next term.at n=16A118632
- Indices of Fibonacci numbers in A073656, i.e., A073656(n) = F(a(n)).at n=14A119755
- p^2-p+1 central polygonal numbers with prime indices A002061(prime(n)).at n=22A119959
- Numbers of the form k^2+k+1 that are the product of two distinct primes.at n=35A176069
- Numbers n for which phi(n)=sigma(n'), where phi is the Euler totient function, sigma is the sum of divisors and n' the arithmetic derivative of n.at n=10A189057
- 7^n mod 10000.at n=4A216130
- Rocket Sequence 34: a(0)=34, a(n) = A073846(a(n-1)).at n=38A261314
- Number of 2 X 2 matrices with all elements in {0,...,n} with permanent = determinant * n.at n=39A280391
- Numbers k such that (184*10^k - 1)/3 is prime.at n=18A282340