11009
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 11
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 11220
- Proper Divisor Sum (Aliquot Sum)
- 211
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10800
- Möbius Function
- 1
- Radical
- 11009
- 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
- 192
- 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) = (10n+1)*(10n+9).at n=10A001535
- Numbers k such that the continued fraction for sqrt(k) has period 29.at n=31A020368
- a(n) = least m such that if r and s in {1/2, 1/5, 1/8, ..., 1/(3n-1)} satisfy r < s, then r < k/m < (k+1)/m < s for some integer k.at n=46A024837
- Numbers that can be expressed as the product of two 3-digit numbers in at least one way.at n=31A033829
- Composite numbers k such that digits in k and in juxtaposition of prime factors of k are the same (apart from multiplicity).at n=17A035141
- n-th 6k+1 prime times n-th 6k-1 prime.at n=12A048629
- Composite numbers n such that sigma(n)+12 = sigma(n+12).at n=7A054902
- Composite numbers k such that both phi(k+12) = phi(k) + 12 and sigma(k+12) = sigma(k) + 12.at n=2A056777
- a(n) = prime(n)*prime(n+3).at n=25A090090
- Smallest number not occurring earlier fitting the repeating pattern "99887766554433221100".at n=39A098782
- Numbers beginning with a vowel in French.at n=11A118557
- Where records occur in A118878.at n=23A119904
- Number of ways to write n as an ordered sum of 1s, 2s, 3s and 4s such that no 2 precedes any 1 and no 3 precedes any 1 or 2.at n=24A123569
- a(1)=0, a(n+1) is smallest nonprime > 2*a(n).at n=13A156321
- Number of binary strings of length n with no substrings equal to 0001 0011 or 1011.at n=21A164458
- Riordan array (f(x), x*g(x)), f(x) is the g.f. of A126952, g(x) is the g.f. of A117641.at n=37A171243
- Numbers k such that exactly three d in the range d <= k/2 exist which divide binomial(k-d-1,d-1) and which are not coprime to k.at n=18A178099
- a(n) = 6*n^2 + 10*n + 5.at n=42A201279
- Third diagonal of Catalan difference table (A059346).at n=9A228338
- a(n) = 384*n + 257.at n=28A229855