11920
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 20
- Divisor Sum
- 27900
- Proper Divisor Sum (Aliquot Sum)
- 15980
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4736
- Möbius Function
- 0
- Radical
- 1490
- Omega Function (Ω)
- 6
- 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
- 94
- 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
- Convolution of A000203 with itself.at n=29A000385
- Fibonacci sequence beginning 1, 31.at n=14A022401
- Smallest m such that A065623(m) = n.at n=28A065624
- Triangle read by rows: T(n,k) is number of ternary words of length n and having k runs of 0's of odd length (0 <= k <= ceiling(n/2); a run of 0's is a subsequence of consecutive 0's of maximal length).at n=45A119914
- Isomers of polyenes attached to benzene (see Cyvin et al. for precise definition).at n=16A121094
- Expansion of x/((1 - x - x^4)*(1 - x)^2).at n=24A145131
- Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of 2 n steps taken from {(-1, -1), (-1, 0), (-1, 1), (1, -1), (1, 0)}.at n=5A151505
- Numbers k such that (2^k + k + 1)*2^k - 1 is prime.at n=7A201357
- Number of 2 X 2 matrices having all elements in {-n,...n} and determinant 3.at n=30A209986
- Number of nX1 0..3 arrays with exactly floor(nX1/2) elements unequal to at least one horizontal or vertical neighbor, with new values introduced in row major 0..3 order.at n=13A222269
- Number of nX2 0..3 arrays with exactly floor(nX2/2) elements unequal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..3 order.at n=6A222788
- T(n,k)=Number of nXk 0..3 arrays with exactly floor(nXk/2) elements unequal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..3 order.at n=34A222794
- Number of 7Xn 0..3 arrays with exactly floor(7Xn/2) elements unequal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..3 order.at n=1A222800
- a(n) = floor(M(g(n-1)+1, ..., g(n))), where M = harmonic mean and g(n) = n^3 + n^2 + n + 1.at n=22A227015
- E.g.f. satisfies: A'(x) = A(x)^7 * A(-x)^3 with A(0) = 1.at n=5A236956
- Beastly reciprocals, or numbers k such that digitsum(1/k) = 666.at n=27A244661
- Number of length 3 0..n arrays with each partial sum starting from the beginning no more than sqrt(3) standard deviations from its mean.at n=22A244942
- 7-step Fibonacci sequence starting with (0,1,0,0,0,0,0).at n=21A251714
- Number of binary strings of length n that begin with an odd-length palindrome.at n=14A254128
- Partial sums of A073602.at n=34A259035