13805
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 18144
- Proper Divisor Sum (Aliquot Sum)
- 4339
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10000
- Möbius Function
- -1
- Radical
- 13805
- 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
- 58
- 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
- Denominators of continued fraction convergents to sqrt(870).at n=4A042681
- a(1) = 1; a(n+1) = sum of terms in continued fraction for the sum of the continued fractions, [a(1); a(2), a(3),...,a(n-1),a(n)] and [a(n); a(n-1), a(n-2),...,a(2), a(1)].at n=16A058081
- Partial sums of A001157: Sum_{j=1..n} sigma_2(j).at n=31A064602
- Numbers n such that phi(n) = b(n,1)^b(n,0) where b(n,1) is the number of 1's in binary representation of n and b(n,0) the number of 0's.at n=43A071638
- a(n) = number of m such that A080737(m) <= 2n.at n=41A080740
- Number of orbits of length n under the map whose periodic points are counted by A061684.at n=4A091315
- Diagonal sums of the number triangle associated to A086617.at n=17A108296
- Column 3 of triangle A123610.at n=12A123613
- Counts of Kekulean pericondensed planar benzenoid hydrocarbons (see reference for precise definition).at n=5A141788
- a(n) = 12*n^2 + 22*n + 11.at n=33A154106
- Number of partitions of n having population standard deviation >= 2.at n=35A238662
- Triangular array: row n gives the coefficients of the polynomial p(n,x) defined in Comments.at n=40A249248
- Numbers m such that there are precisely 7 groups of order m.at n=50A249550
- Number of length 2+2 0..n arrays with the sum of the maximum minus the minimum of adjacent triples multiplied by some arrangement of +-1 equal to zero.at n=13A252178
- Number of partitions of prime(n)^2 into squares of primes.at n=9A276557
- Number of geometrically distinct symmetric open knight's tours on a 4 X (2n-1) chessboard.at n=7A328340
- Number of integer partitions of n with no part divisible by all the others.at n=35A343341
- Numbers m such that 72*m + 1, 576*m + 1, 648*m + 1, 1296*m + 1, and 2592*m + 1 are all primes.at n=6A372187
- a(n) is the maximal absolute value of the determinant of an n X n symmetric Toeplitz matrix having 1 on the main diagonal and all the integers 1, 2, ..., n-1 off-diagonal.at n=6A374241