11921
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 14784
- Proper Divisor Sum (Aliquot Sum)
- 2863
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9360
- Möbius Function
- -1
- Radical
- 11921
- 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
- 50
- 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
- Alkane (or paraffin) numbers l(7,n).at n=25A005994
- a(n) = n*(n-1)*(2*n^2 + 1)/6.at n=14A071245
- Cycle of the inventory sequence (as in A063850) starting with n consists of prime numbers.at n=40A078970
- Continued fraction expansion of a constant x such that the n-th partial quotient equals a(n) = floor(2^n*x), with a(0)=1.at n=13A093053
- Structured hexagonal diamond numbers (vertex structure 5).at n=20A100178
- Partial sums of ceiling(n^2/2) (A000982).at n=41A131941
- a(1)=1, a(n)=a(n-1)+n if n odd, a(n)=a(n-1)+ n^2 if n is even.at n=40A140113
- Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of n steps taken from {(-1, -1), (0, 1), (1, -1)}.at n=15A151375
- n-th prime*8-7 is the square of a prime.at n=41A169583
- Number of (w,x,y,z) with all terms in {0,...,n}, w even, x even, and w+x=y+z.at n=40A212767
- Fundamental discriminants of real quadratic number fields with class number 10.at n=25A218160
- Number of (2+1) X (n+1) 0..1 arrays with every 2 X 2 subblock ne-sw antidiagonal difference nondecreasing horizontally and nw+se diagonal sum nondecreasing vertically.at n=24A258555
- Numbers n such that (2^(n+3) * 5^(n+4) - 1463)/9 is prime (n > 0).at n=6A265123
- Numbers n such that 3n appears earlier than 2n in A280864.at n=40A280755
- Number of subsets of {1..n} of which every subset has a different sum.at n=23A325864
- Odd composite integers m such that A006497(m) == 3 (mod m).at n=20A335669
- Non-palindromic numbers m such that m * repunit of length k is palindromic for all large enough k.at n=49A370053