13609
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 14080
- Proper Divisor Sum (Aliquot Sum)
- 471
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 13140
- Möbius Function
- 1
- Radical
- 13609
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 89
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- Numbers k > 1 such that k mod ord2(k) is even, where ord2(k) is the order of 2 mod k.at n=22A036260
- Frobenius number of the numerical semigroup generated by four consecutive tetrahedral numbers.at n=11A069761
- a(n) = (2*5^n-(4^n-2^n))/2.at n=6A083315
- Convoluted convolved Fibonacci numbers G_6^(r).at n=28A089111
- Square array T(n,k) (row n, column k) read by antidiagonals defined by: T(n,k) is the permanent of the n X n matrix with 1 on the diagonal and k elsewhere; T(0,k)=1.at n=59A090628
- Sum of the sizes of the Durfee squares of all partitions of n into odd parts.at n=49A116465
- Number of n X n binary arrays symmetric under horizontal reflection with all ones connected only in a 110-111-111 pattern in any orientation.at n=11A146273
- a(n) = 42*n^2 + 1.at n=18A158604
- a(n) = 12*n^2 - 8*n + 9.at n=33A167585
- Triangle T(n,k), n>=0, 0<=k<=C(n,2), read by rows: T(n,k) = number of k-length chains in the poset of Dyck paths of semilength n ordered by inclusion.at n=18A193629
- Centered 36-gonal numbers.at n=27A195316
- Number of zero-sum -n..n arrays of 4 elements with adjacent element differences also in -n..n.at n=18A202254
- a(n) = Sum_{y=1..n} Sum_{x=1..n} floor((x^k + y^k)^(1/k)) with k = 2.at n=25A211791
- Numbers k such that k^3 - b2 is a triangular number (A000217), where b2 is the largest square less than k^3.at n=29A233401
- a(n) = 8n^2 - 12n + 1.at n=40A273220
- Ulam numbers k such that 4*k and 16*k are also Ulam numbers.at n=19A287634
- Row sums of A323179.at n=27A323180
- a(n) = Sum_{k=0..floor(n/5)} |Stirling1(n - 4*k,n - 5*k)|.at n=22A357933