16855
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 25
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 20232
- Proper Divisor Sum (Aliquot Sum)
- 3377
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 13480
- Möbius Function
- 1
- Radical
- 16855
- 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
- 159
- 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) = 11*a(n-1) + 6*a(n-2).at n=5A015598
- a(n) = a(n-3) + a(n-4), with a(0)=1, a(1)=a(2)=0, a(3)=1.at n=55A017817
- Numbers k such that 225*2^k+1 is prime.at n=37A032489
- Numerators of continued fraction convergents to sqrt(129).at n=9A041234
- Numerators of continued fraction convergents to sqrt(516).at n=9A041986
- Quintisection of 1/(1-x^3-x^4).at n=11A099101
- Expansion of x/(1 - 2*x^2 - x^3 + x^4).at n=27A122514
- Number of (n+2)X3 0..3 arrays with every 3X3 subblock having three equal elements in a row horizontally, vertically, diagonally or antidiagonally exactly three ways, and new values 0..3 introduced in row major order.at n=4A204635
- Number of (n+2) X 7 0..3 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..3 introduced in row major order.at n=0A204639
- T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock having three equal elements in a row horizontally, vertically, diagonally or antidiagonally exactly three ways, and new values 0..3 introduced in row major order.at n=10A204642
- T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock having three equal elements in a row horizontally, vertically, diagonally or antidiagonally exactly three ways, and new values 0..3 introduced in row major order.at n=14A204642
- Number of compositions of n into parts 3,4 where both parts are always present.at n=55A245487
- Number of nX6 0..1 arrays with every element unequal to 0, 1, 3, 5 or 7 king-move adjacent elements, with upper left element zero.at n=7A304929
- a(n) = Sum_{1 <= x_1, x_2 <= n} gcd(x_1, x_2, n)^5.at n=6A372927
- Expansion of (1 - x) / ((1 - x)^3 - x^4).at n=17A375169