1805
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 2286
- Proper Divisor Sum (Aliquot Sum)
- 481
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 1368
- Möbius Function
- 0
- Radical
- 95
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 2
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
- 55
- 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
- no
- Odd
- yes
Appears in sequences
- Number of spanning trees in C_5 X P_n.at n=1A003733
- Complexity of doubled cycle (regarding case n = 2 as a multigraph).at n=4A006235
- Successive states of the Rule 110 cellular automaton defined by 000, 001, 010, 011, ..., 111 -> 0,1,1,1,0,1,1,0 when started with a single ON cell.at n=10A006978
- a(n) is the smallest positive number such that the sum of A001032(n) consecutive squares starting with a(n)^2 is a square.at n=42A007475
- Coordination sequence T1 for Zeolite Code RUT.at n=28A009897
- Number of (unordered) triples of integers from [1,n] with no common factors between pairs.at n=32A015617
- a(n)-th squarefree is sum of first k squarefrees for some k.at n=36A020643
- Convolution of A023532 and (F(2), F(3), F(4), ...).at n=14A023600
- a(n) = dot_product(1,2,...,n)*(6,7,...,n,1,2,3,4,5).at n=13A026046
- Sum of numbers between the two n's in A026272.at n=39A026275
- a(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026300.at n=4A026940
- Numerator of Sum_{p prime, p-1|n} 1/p.at n=41A027759
- Numerator of sum_{p prime, p-1 divides 2*n} 1/p.at n=20A027761
- a(n) = n + (n+1)^2.at n=41A028387
- Numbers k that divide the (right) concatenation of all numbers <= k written in base 19 (most significant digit on left).at n=31A029464
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 16.at n=41A031514
- Numbers k such that 141*2^k+1 is prime.at n=34A032420
- Concentric pentagonal numbers: floor( 5*n^2 / 4 ).at n=38A032527
- a(n) = 5*n^2.at n=19A033429
- A006318(n) - 1.at n=6A035011