13005
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 18
- Divisor Sum
- 23946
- Proper Divisor Sum (Aliquot Sum)
- 10941
- 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
- 255
- 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
- no
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 138
- 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
- Volume of a certain rational polytope whose points with given denominator count certain sets of Standard Tableaux.at n=6A012249
- Expansion of Product_{m>=1} 1/(1 + m*q^m)^9.at n=10A022701
- Reverse and add (in binary) - written in base 10.at n=18A035522
- Odd composite numbers divisible by the sum of their prime factors (counted with multiplicity).at n=38A046347
- Non-palindromic number and its reversal are both multiples of 17.at n=32A062915
- Number of unlabeled alternating octopuses with n black nodes.at n=7A091469
- Absolute row sums of triangle A104505, which is equal to the right-hand side of the triangle A084610 of coefficients in (1+x-x^2)^n.at n=12A104508
- Number of pyramids of the first kind in all paths from (0,0) to (3n,0) that stay in the first quadrant (but may touch the horizontal axis), consisting of steps u=(2,1),U=(1,2), or d=(1,-1) (a pyramid of the first kind is a sequence u^pd^p for some positive integer p, starting at the x-axis).at n=5A108453
- Triangle read by rows: rows = inverse binomial transforms of columns of A309220.at n=37A118980
- Numbers m such that greatest prime divisor of (m-th prime + 1) is 3.at n=27A121820
- Numbers k such that prime(k) + prime(k+1) is a perfect power.at n=40A132746
- Number of coincidence-free length n lists of 3-tuples with all numbers 1,...,n in tuple position k, for k=1,2,3.at n=4A135809
- Triangle of numbers of coincidence-free length n-m lists of m-tuples with all numbers 1,...,n-m in tuple position k, for k=1..m.at n=31A135814
- Composites that are the sum of two, three, four and five consecutive composite numbers.at n=18A151745
- Numbers k such that k-4, k-2, k+2 and k+4 are prime.at n=12A173037
- Number of n X 1 0..4 arrays with each element equal to the number its horizontal and vertical neighbors less than itself.at n=12A196423
- E.g.f.: Sum_{n>=0} a(n) * (cos(n*x)-sin(n*x)) * x^n/n! = 1/(1-x).at n=5A219504
- Number of terms of 2^j + 3^k <= 10^n.at n=42A219835
- Location (x,y) of the first n x n square of composite Gaussian integers in the first quadrant.at n=29A225073
- Location y of the first n x n square of composite Gaussian integers in the first quadrant.at n=14A225075