1806
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 4224
- Proper Divisor Sum (Aliquot Sum)
- 2418
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 504
- Möbius Function
- 1
- Radical
- 1806
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- yes
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 117
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = 3^n - 3*2^n + 3.at n=7A001117
- Number of n-node connected unicyclic graphs.at n=8A001429
- Oblong (or promic, pronic, or heteromecic) numbers: a(n) = n*(n+1).at n=42A002378
- Denominators of Bernoulli numbers B_{2n}.at n=21A002445
- a(n) = n*phi(n).at n=42A002618
- a(n) = 2*n*(2*n+1).at n=21A002943
- Number of unrooted triangulations with reflection symmetry of a pentagon with n internal nodes.at n=7A005506
- Large Schröder numbers (or large Schroeder numbers, or big Schroeder numbers).at n=6A006318
- Numerators of worst case for Engel expansion.at n=26A006539
- Denominators of Bernoulli numbers B_0, B_1, B_2, B_4, B_6, ...at n=22A006954
- a(n) = a(n-1)^2 + a(n-1), a(0)=1.at n=4A007018
- Coordination sequence T3 for Zeolite Code AEL.at n=28A008006
- Coordination sequence T2 for Zeolite Code AST.at n=30A008037
- Coordination sequence T2 for Zeolite Code EAB and OFF.at n=31A008083
- Coordination sequence T1 for Zeolite Code EMT.at n=35A008086
- Coordination sequence T1 for Zeolite Code PAU.at n=31A008219
- Coordination sequence T4 for Zeolite Code TON.at n=26A008244
- a(n) = lcm(n, phi(n)).at n=42A009262
- Coordination sequence T2 for Zeolite Code WEI.at n=30A009918
- Coordination sequence for sigma-CrFe, Position Xf.at n=11A009958