16555
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
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 25344
- Proper Divisor Sum (Aliquot Sum)
- 8789
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10080
- Möbius Function
- 1
- Radical
- 16555
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- no
- 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) = n*(9*n-2).at n=43A013656
- Quasi-Carmichael numbers to base -5: squarefree composites n such that prime p|n ==> p+5|n+5.at n=4A029565
- Values of continued fraction for Pi/2 associated with the records in A096464.at n=6A096731
- Fifth column (m=4) of (1,6)-Pascal triangle A096956.at n=19A096958
- Smallest order of the cyclotomic polynomial whose maximal coefficient in absolute value is n.at n=14A136418
- Row sums of A163357 and A163359 divided by 4.at n=42A163477
- Highest scoring cribbage hand with n cards.at n=18A195676
- a(n) = smallest k having at least four prime divisors d such that (d + n) | (k + n).at n=4A202159
- The least k such that the polynomial cyclotomic(k,x) has n different coefficients.at n=29A231611
- a(n) = binomial(10*n+5,n)/(2*n+1).at n=4A234528
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 454", based on the 5-celled von Neumann neighborhood.at n=39A272278
- Numbers k such that A317993(k) sets a new record; numbers k such that (Z/mZ)* = (Z/kZ)* has more solutions for m than all k' < k, where (Z/mZ)* is the multiplicative group of integers modulo m.at n=10A328420
- First occurrence of n in A345079, or -1 if n does not occur in A345079.at n=29A345080
- Minimum number of spanning trees in a 3-connected graph on n nodes.at n=9A359704
- Expansion of g.f. A(x) satisfying A( x^2*(1 + 3*x)*A(x) )^5 = A( x^3*(1 + 5*x)*A(x)^2 )^3.at n=6A370535
- a(n) = Sum_{k=0..floor(3*n/11)} binomial(3*n-10*k,k).at n=21A392350