16245
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 18
- Divisor Sum
- 29718
- Proper Divisor Sum (Aliquot Sum)
- 13473
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8208
- Möbius Function
- 0
- Radical
- 285
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 40
- 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
- no
- Odd
- yes
Appears in sequences
- Expansion of tanh(log(1+x))/cos(x).at n=9A009780
- Expansion of e.g.f.: tanh(log(1+x))/cosh(x).at n=9A009781
- Gaps of 9 in sequence A038593 (lower terms).at n=11A038657
- Numbers whose base-5 representation contains exactly three 0's and three 4's.at n=13A045217
- Given the infinite continued fraction (1+i)+((1+i)/(1+i)+((1+i)/((1+i)+...)))), where i is the square root of (-1), this is the numerator of the imaginary part of the convergents.at n=13A093726
- Expansion of x*(1+8*x)/((1-8*x)*(1+11*x+64*x^2)).at n=5A112259
- Matrix cube of triangle A113340.at n=32A113360
- Column 4 of triangle A113360, also equals column 1 of A113360^3.at n=3A113364
- Partial sums of A051941.at n=18A136105
- a(n) is the smallest positive number such that a(n)*n is an anagram of a(n)*9.at n=24A175698
- Triangular array read by rows: T(n,k) is the number of functions f:{1,2,...,n} -> {1,2,...,n} that have exactly k 2-cycles for n >= 0 and 0 <= k <= floor(n/2).at n=13A185025
- The number of NE partitions of n (see Comments).at n=35A239329
- Number of squares of all sizes in polyominoes obtained by union of two pyramidal figures (A092498) with intersection equals A002623.at n=35A260918
- Number of orbits of Aut(Z^7) as function of the infinity norm n of the representative lattice point of the orbit, when the cardinality of the orbit is equal to 80640.at n=20A266396
- Decimal representation of the x-axis, from the left edge to the origin, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 283", based on the 5-celled von Neumann neighborhood.at n=13A280529
- Number of regular polygons that can be drawn with vertices on a centered hexagonal grid with side length n.at n=9A339483
- Positions k where A348733(k) is not multiplicative.at n=15A348740
- Odd numbers k such that sigma(k) + sigma(k+2) > 2*sigma(k+1); odd terms in A053228.at n=37A358395
- The n-th term in the trajectory of the n-th prime P under the 'Px+1' map.at n=41A368159
- Terms k of A228058 for which A048146(k)+A162296(k) >= 2*k, where A048146 is the sum of non-unitary divisors, and A162296 is the sum of divisors that have a square factor.at n=21A389219