11918
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
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 18360
- Proper Divisor Sum (Aliquot Sum)
- 6442
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5800
- Möbius Function
- -1
- Radical
- 11918
- Omega Function (Ω)
- 3
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 125
- 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
- Partial sums of binary rooted tree numbers.at n=16A014167
- Numbers k such that sigma(k) = sigma(k+8).at n=18A015876
- Composite numbers k such that phi(k + d(k)) = phi(k) + d(k), where phi() = A000010(), d() = A000005().at n=18A063702
- Number of partitions of n into sums of products.at n=26A066815
- Irregular triangle in which row n has the values of k>n such that Sum_{i=n..k} i^2 is a square.at n=45A184763
- Numbers n such that 8^n + 3 is prime.at n=23A217354
- Number of n X 2 arrays of the minimum value of corresponding elements and their horizontal, vertical or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and columns, 0..2 n X 2 array.at n=20A219293
- Numbers n such that 4n + 1, 4n + 2 and 4n + 3 are not squarefree.at n=24A258332
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 966", based on the 5-celled von Neumann neighborhood.at n=33A273837
- a(n) = least value of k such that tau(k) = A000594(k) == n mod 23.at n=19A278578
- Intersection of A003052 and A283002.at n=27A283003
- Numbers k such that (14*10^k + 61)/3 is prime.at n=20A285378
- a(n) is the sum of the base-b representations of n for 2 <= b <= n+1 read in base ten.at n=26A289335
- a(n) is the smallest possible side x in a family of triangles with integer sides x, y < x, x-y < z < x+y, such that exactly n pairs of triangles with equal area exist in this family.at n=42A375748