11561
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 12624
- Proper Divisor Sum (Aliquot Sum)
- 1063
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10500
- Möbius Function
- 1
- Radical
- 11561
- 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
- 68
- 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
- Expansion of (1/(1-x^2))*Product_{m>=0} 1/(1-x^(2m+1)).at n=47A038348
- Number of walks of length n between two nodes at distance 2 in the cycle graph C_7.at n=14A095307
- Values of x in solutions (x,y,z) to the Diophantine equation x^3-x^2+y^3-y^2=z^3-z^2, with 1<x<y<z.at n=24A138667
- a(n) = 10*n^2 + 1.at n=34A158187
- a(n) = 289n + 1.at n=39A158255
- a(n) = 40*n^2 + 1.at n=17A158602
- G.f.: A(x) = exp( Sum_{n>=1} (1 + 2*A006519(n)*x)^n * x^n/n ) where A006519(n) is the highest power of 2 dividing n.at n=10A163572
- Nonprime numbers with all divisors starting and ending with digit 1.at n=10A208261
- Number of (w,x,y,z) with all terms in {1,...,n} and |w-x|=2|x-y|-|y-z|.at n=25A212577
- Number of (w,x,y) with all terms in {0,...,n} and |w-x| + |x-y| != w+x+y.at n=22A213480
- For n > 1 the sum of t := floor(n/2) + 1 consecutive previous terms, the leading t terms when n is even, the immediately-preceding t terms when n is odd; a(0) = 0, a(1) = 1.at n=46A238834
- Records in A098550.at n=38A248647
- Values of A098550 where A098550(k)/k reaches a record high.at n=13A251415
- Number of active (ON, black) cells at stage 2^n-1 of the two-dimensional cellular automaton defined by "Rule 419", based on the 5-celled von Neumann neighborhood.at n=6A272046
- a(n) = Sum_{k=0..floor(n/7)} binomial(n,7*k).at n=16A306852
- Composite numbers k with its divisors having the property that the last digit of every divisor is the same as the first digit of the next divisor.at n=10A307858
- a(n) = Sum_{k=0..n} binomial(2*n,7*k).at n=8A387845