11909
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
- 1
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 11910
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 11908
- Möbius Function
- -1
- Radical
- 11909
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- 143
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- yes
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1427
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- a(0) = 1, a(n) = 27*n^2 + 2 for n>0.at n=21A010017
- Numbers k such that the continued fraction for sqrt(k) has period 47.at n=18A020386
- Primes that remain prime through 3 iterations of the function f(x) = 2*x + 1.at n=13A023272
- Primes of the form k^2 + (k+1)^2 + (k+2)^2 = 3*(k+1)^2+2.at n=9A027864
- Numerators of continued fraction convergents to sqrt(613).at n=8A042176
- Primes that yield a different prime when rotated by 180 degrees.at n=36A048890
- Primes p such that there is no Carmichael number pqr, p<q<r q, r primes.at n=13A051663
- Primes starting a Cunningham chain of the first kind of length 4.at n=8A059763
- Numbers n such that n, 2n+1, 3n+2, 4n+3 are primes.at n=6A067257
- Primes that are still primes when turned upsided down.at n=40A080788
- Squares of the norms of Gaussian primes from A107629.at n=28A107630
- Smallest primes starting a complete three iterations Cunningham chain of the first or second kind.at n=13A110025
- Beginning with 3, least member of A007500 such that concatenation of first n terms and its digit reversal both are primes.at n=13A111383
- Primes for which the weight as defined in A117078 is 15 and the gap as defined in A001223 is 14.at n=16A118380
- Emirps with only nonprime digits (i.e., 0, 1, 4, 6, 8, 9).at n=38A128390
- Primes of the form 2*p(k)+3*p(k+1)+4*p(k+2) for some k, where p(k)=A000040(k).at n=38A138665
- Primes congruent to 19 mod 41.at n=36A142216
- Primes congruent to 41 mod 43.at n=28A142290
- Primes congruent to 18 mod 47.at n=29A142369
- Primes congruent to 2 mod 49.at n=35A142415