11005
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 7
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 13824
- Proper Divisor Sum (Aliquot Sum)
- 2819
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8400
- Möbius Function
- -1
- Radical
- 11005
- 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
- 174
- 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
- Pseudoprimes to base 26.at n=46A020154
- a(n) = (d(n)-r(n))/2, where d = A026063 and r is the periodic sequence with fundamental period (1,1,0,1).at n=40A026064
- Squarefree n such that the elliptic curve n*y^2 = x^3 - x arising in the "congruent number" problem has rank 3.at n=17A062693
- Integers i > 1 for which there is no prime p such that i is a solution mod p of x^4 = 2.at n=20A065903
- Number of pairs of rabbits when there are 3 pairs per litter and offspring reach parenthood after 3 gestation periods; a(n) = a(n-1) + 3*a(n-3), with a(0) = a(1) = a(2) = 1.at n=16A084386
- Numbers beginning with a vowel in French.at n=7A118557
- Numbers of the form m = p1 * p2 * p3 where for each d|m we have (d+m/d)/2 prime and p1 < p2 < p3 each prime.at n=40A128284
- Indices of centered heptagonal numbers (A069099) which are also heptagonal numbers (A000566).at n=4A133272
- Numbers k such that k and k^2 use only the digits 0, 1, 2 and 5.at n=44A136822
- Numbers k such that k and k^2 use only the digits 0, 1, 2, 5 and 7.at n=53A136824
- Numbers k such that k and k^2 use only the digits 0, 1, 2, 5 and 8.at n=53A136825
- Numbers k such that k and k^2 use only the digits 0, 1, 2, 5 and 9.at n=59A136826
- Number of connected graphs on n unlabeled nodes that contain at least two cycles.at n=7A140636
- 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, -1), (0, 0, 1), (1, 0, 0), (1, 1, -1)}.at n=8A149964
- 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), (-1, 0), (0, 1), (1, -1), (1, 0)}.at n=9A151430
- Numbers k such that the string k modulo 1000 is found at position k in the decimal digits of Pi.at n=31A153226
- X-toothpick sequence on Z^3 lattice (see Comments for precise definition).at n=31A160170
- a(n) = (prime(n))^2 - (nonprime(n))^2.at n=29A161757
- a(1) = 1, and for each k >=2, a(k) is the smallest number n such that n/sin(n) > a(k)/sin(a(k)), so that a(1)/sin(a(1)) > a(2)/sin(a(2)) > ... > a(k)/sin(a(k)) > ...at n=29A172445
- Numbers m such that the sum of the first k odd primes = m-th odd prime.at n=19A179321