13209
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 21888
- Proper Divisor Sum (Aliquot Sum)
- 8679
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6912
- Möbius Function
- 1
- Radical
- 13209
- 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
- 45
- 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
- Number of partitions of n into parts of 3 kinds.at n=13A000716
- Fermat coefficients.at n=16A000970
- a(n) = (10n+1)*(10n+9).at n=11A001535
- Logarithmic numbers: expansion of the e.g.f. -log(1-x) * e^(-x).at n=9A002741
- Molien series for cyclic group of order 5.at n=33A008646
- a(n) = floor(C(n,4)/5).at n=37A011795
- Exponential generating function is -f(x) * Integral_{t = 0..x} exp(exp(-t) - 1) dt, where f(x) = exp(1 - x - exp(-x)) is the exponential generating function for A014182.at n=10A014619
- a(n) = n*(15*n - 1)/2.at n=42A022272
- Expansion of Product_{m>=1} 1/(1 - m*q^m)^7.at n=6A022731
- Number of labeled servers of dimension 17.at n=3A027404
- Divide odd numbers into groups with prime(n) elements and add together.at n=11A034960
- a(n) = T(n,5), array T as in A051168; a count of Lyndon words; aperiodic necklaces with 5 black beads and n-5 white beads.at n=33A051170
- Number of finite positive integer sequences b(1),...,b(k), with k <= n and b(1)*b(2)*...*b(k) <= n.at n=13A064453
- Number of divisors of n equals the average of distinct prime factors of n.at n=40A067547
- A014486-indices of A083932-trees.at n=36A083934
- Denominator of sum of reciprocals of first n 5-simplex numbers A000389.at n=32A118432
- a(n) = n * Fibonacci(n) - Sum_{i=0..n} Fibonacci(i).at n=16A122491
- a(n) = RMS( A141391(1) through A141391(n) ).at n=38A141392
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 1, -1), (1, 0, 1), (1, 1, -1), (1, 1, 1)}.at n=7A150917
- a(n) = n*(16*n^2 + 3*n - 13)/6.at n=17A172078