11919
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 16560
- Proper Divisor Sum (Aliquot Sum)
- 4641
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7616
- Möbius Function
- -1
- Radical
- 11919
- 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
- no
- Odd
- yes
Appears in sequences
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 11 ones.at n=27A031779
- a(n) = a(1) + a(2) + ... + a(n-1) + a(m) for n >= 3, where m = 2*n - 2 - 2^(p+1) and p is the unique integer such that 2^p < n-1 <= 2^(p+1), starting with a(1) = a(2) = 1.at n=13A049943
- Subminimal numbers, from minimal numbers by analogy with subfactorials.at n=47A079717
- Column l=3 of irregular triangle in A133709.at n=10A133710
- 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, 0), (1, 0, 1), (1, 1, -1)}.at n=9A148823
- Toothpick sequence in the three-dimensional grid.at n=49A160160
- A156977/3.at n=5A164565
- Number of partitions of 1 into up to n powers of 1/2.at n=17A173404
- Floor-Sqrt transform of large Schroder numbers (A006318).at n=13A192673
- Number of ordered triples (w,x,y) with all terms in {-n,...-1,1,...,n} and w+x+y>2.at n=15A211614
- Floor of the value of Riemann's xi function at n.at n=23A236212
- a(n) = A255448(2^n-1).at n=7A255449
- Numbers k with the property that the square root of the product of the digits of k is equal to the sum of the square roots of its digits.at n=22A281745
- Numbers using only digits 1 and 9.at n=35A284294
- Expansion of Product_{k>=1} ((1 + x^k) / (1 - x^(4*k)))^k.at n=18A285458
- Numbers that contain exactly one pair of identical digits x and a triple of identical digits y (x not equal y).at n=39A291312
- Number of nX3 0..1 arrays with every element equal to 3, 4, 5, 6 or 8 king-move adjacent elements, with upper left element zero.at n=16A298897
- Number of prime parts in the partitions of n into 10 parts.at n=38A309439
- Numbers whose multiset multisystem (A302242) is crossing.at n=28A324170
- Number of maximal subsets of {1..n} containing no sums or products of distinct elements.at n=29A326025