16646
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 30240
- Proper Divisor Sum (Aliquot Sum)
- 13594
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6720
- Möbius Function
- 1
- Radical
- 16646
- 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
- 66
- 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
- yes
- Odd
- no
Appears in sequences
- dot_product(n,n-1,...2,1)*(7,8,...,n,1,2,3,4,5,6).at n=34A026066
- Number of rational points of Klein curve over GF(2^n).at n=13A048635
- G.f.: Product((1+x^i)/(1-x^i),i=1..n-1)/(1-x^n), with n = 5.at n=39A091773
- Fourth column (m=3) of (1,6)-Pascal triangle A096956.at n=40A096957
- Numbers k such that 7*10^k + 9 is prime.at n=28A097954
- Values of y in x^2 - 49 = 2*y^2.at n=14A106526
- Triangle read by rows: T(n,k) is the number of Motzkin paths of length n and having k weak ascents (1 <= k <= ceiling(n/2)).at n=44A114690
- 1/4 the number of (n+1) X 4 binary arrays with all 2 X 2 subblock sums the same.at n=14A183980
- 41 times triangular numbers.at n=28A195038
- Years >= 1801 in which Christmas falls in Sukkot.at n=27A222419
- Composite squarefree numbers n such that p(i)-4 divides n+4, where p(i) are the prime factors of n.at n=14A225704
- a(n) is the second number in a triple consisting of 3 numbers, which when squared are part of a right diagonal of a magic square of squares.at n=4A273182
- Number of integers in n-th generation of tree T(3^(-1/2)) defined in Comments.at n=47A274157
- Expansion of exp( Sum_{n>=1} -sigma(8*n)*x^n/n ) in powers of x.at n=32A283168
- Decimal representation of the diagonal from the corner to the origin of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 30", based on the 5-celled von Neumann neighborhood.at n=33A285538
- Squarefree numbers k such that alpha(k) = lambda(k), where alpha(k) = LCM of all (p+1) for primes p dividing k, and lambda(k) = A002322(k).at n=4A287514
- a(n) = (1/24)*(n + 3)*(3*n^3 + 5*n^2 - 6*n + 16).at n=17A290061
- Number of ways to write n as an ordered sum of 7 primes.at n=28A340963
- Expansion of (1/x) * Series_Reversion( x * (1-2*x) / (1+3*x)^2 ).at n=4A386769
- a(n) is the number of 5 element sets of distinct integer-sided trapezoids each of area less than 3*n^2 whose base angles are 60 degrees that fill a regular hexagon of side n units.at n=29A390763