13088
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 25830
- Proper Divisor Sum (Aliquot Sum)
- 12742
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6528
- Möbius Function
- 0
- Radical
- 818
- Omega Function (Ω)
- 6
- 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
- 45
- 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
- a(n) = [ (3rd elementary symmetric function of P(n))/(first elementary symmetric function of P(n)) ], where P(n) = {first n+2 primes}.at n=12A024453
- Number of partitions of n in which the least part is even.at n=45A026805
- Expansion of (theta_3(z)*theta_3(3z)*theta_3(9z)+theta_2(z)*theta_2(3z)*theta_2(9z))^4.at n=45A028705
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 57.at n=27A031555
- Fifth column of A046741.at n=7A062125
- a(n) = floor(X/Y) where X = concatenation in decreasing order of (2n)-th even number to (n+1)-th even number and Y = that of first n even numbers in increasing order.at n=7A067092
- Smaller side not divisible by 37 of right triangles with integer sides and integer side inscribed squares with two vertices on the hypotenuse.at n=16A123697
- The Wiener index of a chain of n squares joined at vertices (i.e., joined like <><><>...<>; here <> is a square!).at n=15A143943
- a(n) = Sum_{k=1..n} (k+2)!/k! = Sum_{k=1..n} (k+2)*(k+1).at n=32A180118
- Triangle read by rows: T(n,k) is the number of non-equivalent regular polygons with n+1 edges, one of which is rooted, which are dissected by non-intersecting diagonals into k regions, such that two such polygons are identified up to reflection along the rooted edge and twisting along the diagonals that does not affect the root edge (for 1 <= k <= n-1 and n >= 2).at n=59A232206
- 5*n analog to Keith numbers.at n=18A282760
- Number of canonical forms for separation coordinates on hyperspheres S_n, ordered by increasing number of independent continuous parameters.at n=61A295380
- Numbers k not ending in zero that are a substring of k*(k+1).at n=8A305670
- Triangle read by rows: T(0,0) = 1; T(n,k) = T(n-1, k) + 2*T(n-1, k-1) + 3*T(n-1, k-2) + 4*T(n-1, k-3) + 5*T(n-1, k-4) + 6*T(n-1, k-5) for k = 0..5*n; T(n,k)=0 for n or k < 0.at n=44A319092
- Number of compositions (ordered partitions) of n into distinct parts, the least being 5.at n=50A339166
- Number of polycubes of size n and symmetry class K.at n=13A376974
- Index of n-th prime in A386482, or -1 if that prime is missing.at n=61A386483