17726
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 26592
- Proper Divisor Sum (Aliquot Sum)
- 8866
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8862
- Möbius Function
- 1
- Radical
- 17726
- 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
- 79
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = a(n-2) + a(n-3), with a(0) = 0, a(1) = 1, a(2) = 4.at n=34A007309
- Row sums of triangle A091492.at n=47A091493
- Expansion of g.f. Product((1+x^i)/(1-x^i),i=1..n-1)/(1-x^n), with n = 6.at n=31A091774
- "Ceiling of hypotenuses": a(n) = ceiling(sqrt(a(n-1)^2 + a(n-2)^2)), a(1)=1, a(2)=3.at n=36A104805
- Triangle T(n,k), 0 <= k <= n, read by rows, defined by: T(0,0) = 1, T(n,k) = 0 if n<k, T(n,0) = T(n-1,0) + T(n-1,1) and for k >= 1: T(n,k) = T(n-1,k-1) + x*T(n-1,k) + T(n-1,k+1) with x = 3.at n=38A110877
- Expansion of 1/(1 - x - x^6 - x^11 + x^12).at n=41A175773
- Triangle T(n,k): the coefficient of [t^n] [x^k] of 2^(n+5) *n! *exp(t*(1+t)*x) / (3+exp(t*(1+t))).at n=21A178603
- Generalized Riordan array based on the binomial transform of the Fine's numbers A000957.at n=59A187914
- Number of (n+2) X 4 0..1 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically, diagonally or antidiagonally exactly three ways, and new values 0..1 introduced in row major order.at n=18A204748
- Indices of primes in the tribonacci-like sequence, A020992.at n=10A233554
- G.f.: 1 + Sum_{n>=1} a(n)*x^n/(1 - x^n) = Product_{n>=1} (1 + x^n)/(1 - x^n).at n=22A300274
- a(n) = [x^n] Product_{k>=1} (1 + x^k)*(1 - x^(n*k))/((1 - x^k)*(1 + x^(n*k))).at n=23A304627