9809
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 26
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 10404
- Proper Divisor Sum (Aliquot Sum)
- 595
- 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
- 9216
- Möbius Function
- 1
- Radical
- 9809
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 166
- 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
- Sum of digits of n-th term in Look and Say sequence A005150.at n=30A004977
- Stella octangula numbers: a(n) = n*(2*n^2 - 1).at n=17A007588
- Geometric mean of phi(n) and sigma(n) is an integer, n odd.at n=24A015705
- Pseudoprimes to base 24.at n=36A020152
- Pseudoprimes to base 65.at n=37A020193
- Pseudoprimes to base 71.at n=43A020199
- Strong pseudoprimes to base 27.at n=12A020253
- Strong pseudoprimes to base 65.at n=11A020291
- Strong pseudoprimes to base 71.at n=11A020297
- a(n) = n*(17*n - 1)/2.at n=34A022274
- Numbers k such that 101*2^k+1 is prime.at n=25A032400
- Numbers k such that 231*2^k+1 is prime.at n=44A032492
- Denominators of continued fraction convergents to sqrt(958).at n=11A042855
- a(n)=T(n,n+3), array T as in A049735.at n=38A049743
- Number of factorizations with 2 levels of parentheses indexed by prime signatures. A050338(A025487).at n=32A050339
- Numbers n such that 85*2^n-1 is prime.at n=11A050568
- Numbers k such that the period of the continued fraction for sqrt(2)*k (A064848) is 2.at n=42A065029
- Numbers k such that phi(k) and sigma(k) are both perfect squares.at n=12A067781
- Number of primes of the form 30k + 17 less than 10^n.at n=5A091169
- Values of x in x^2 - 289 = 2*y^2.at n=11A106527