16681
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 19072
- Proper Divisor Sum (Aliquot Sum)
- 2391
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 14292
- Möbius Function
- 1
- Radical
- 16681
- 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
- 115
- 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 period of the continued fraction for sqrt(k) contains exactly 78 ones.at n=14A031846
- Numbers k such that k!!! + 1 is prime (0 is included by convention).at n=37A037083
- a(n) = (1/3!)*(n^3 + 24*n^2 + 107*n + 90), compare A059604.at n=39A059605
- Number of solutions to rev(x^2)=rev(x)^2 below 10^n.at n=10A098690
- a(n) is the smallest integer k such that the n-th (forward) difference of the partition sequence A000041 is positive from k onwards.at n=31A119712
- Number of length-n 0..6 arrays with no adjacent pair x,x+1 repeated.at n=4A269654
- T(n,k) = number of length-n 0..k arrays with no adjacent pair x,x+1 repeated: infinite square array read by falling antidiagonals.at n=49A269656
- Number of length-5 0..n arrays with no adjacent pair x,x+1 repeated.at n=6A269658
- Number of maximal matchings in the n-antiprism graph.at n=9A284701
- a(n) = Sum_{k=1..n} sigma_3(k) * floor(n/k).at n=14A356043