16565
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
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 19884
- Proper Divisor Sum (Aliquot Sum)
- 3319
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 13248
- Möbius Function
- 1
- Radical
- 16565
- 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
- 128
- 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
- Numbers k such that the continued fraction for sqrt(k) has period 41.at n=33A020380
- Number of strong elementary edge-subgraphs in Moebius ladder M_n.at n=10A020880
- Shifts left 2 places under "DHK" (bracelet, identity, unlabeled) transform.at n=18A032258
- Expansion of (2 + 2*x - 3*x^2) / (1 - 2*x - x^2 + x^3).at n=11A033304
- Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 17.at n=18A051982
- a(n) = 10*n^2 - 6*n + 1.at n=40A087348
- 1/3 of the number of permutations of 2 indistinguishable copies of 1..n with exactly 4 local maxima.at n=4A152496
- 7^n - 3^n + 1.at n=5A155612
- Sum of n-th powers of the three roots of x^3-2*x^2-x+1.at n=12A274975
- Semiprime numbers whose digit string can be partitioned into three parts such that the product of the first two parts equals the third part.at n=38A280636
- One of the two successive approximations up to 2^n for 2-adic integer sqrt(-7). This is the 1 (mod 4) case.at n=13A318960
- Total number of nodes summed over all lattice paths from (0,0) to (i,n-2*i) that do not go above the diagonal x=y using steps in {(1,0), (0,1)}.at n=21A357655