16820
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 18
- Divisor Sum
- 36582
- Proper Divisor Sum (Aliquot Sum)
- 19762
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6496
- Möbius Function
- 0
- Radical
- 290
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 3
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
- 97
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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
- Number of Hamiltonian paths in C_5 X P_n.at n=3A003732
- Sum of consecutive nonsquares.at n=20A048395
- Expansion of g.f.: 1/((1 - x - x^2 + x^4 - x^6)*(1 - x^2 + x^4 + x^5 - x^6)).at n=24A147606
- Totally multiplicative sequence with a(p) = 9p+2 for prime p.at n=17A166676
- Augmentation of the triangle A062344. See Comments.at n=31A193601
- a(n) = 20*n^2.at n=29A195322
- Row sums of the triangle in A199332.at n=39A199771
- Number of 0..n arrays x(0..2) of 3 elements with each no smaller than the sum of its previous elements modulo (n+1).at n=38A200252
- Number of (w,x,y,z) with all terms in {1,...,n} and w + x = 2y + 2z.at n=41A212561
- Number of triples (w,x,y) with all terms in {0,...,n} and w >= floor((x+y)/3).at n=28A212972
- Total number of parts in all partitions of n with at least one distinct part.at n=24A220477
- Composites whose prime factorization in base 3 is an anagram of the number in base 3.at n=31A260047
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 446", based on the 5-celled von Neumann neighborhood.at n=32A272250
- a(n) = sigma_2(3*n).at n=40A283237
- Practical numbers z such that z^2 = x^2 + y^2 for some practical numbers x and y with gcd(x,y,z) = 4.at n=27A294112
- a(n) = one-half of the number of cells in the central rectangle of the graph described in row 2n+1 of A333288.at n=23A337640
- Positions k where A348733(k) is not multiplicative.at n=16A348740
- Indices where prime(n) first appears in A373902.at n=32A371618
- Sum of the n-th maximal run of adjacent (increasing by one at a time) non-perfect-powers.at n=26A375705