1686
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 3384
- Proper Divisor Sum (Aliquot Sum)
- 1698
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 560
- Möbius Function
- -1
- Radical
- 1686
- 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
- 42
- 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
- Cluster series for hexagonal lattice.at n=7A003202
- a(n) = round(n*phi^14), where phi is the golden ratio, A001622.at n=2A004949
- a(n) = ceiling(n*phi^14), where phi is the golden ratio, A001622.at n=2A004969
- a(n) = a(n-1) + a(n-9) for n >= 9; a(n) = 1 for n=0..7; a(8) = 2.at n=42A005711
- Coordination sequence T3 for Zeolite Code FER.at n=25A008108
- Coordination sequence T2 for Zeolite Code PAU.at n=30A008220
- Coordination sequence T3 for Zeolite Code PAU.at n=30A008221
- Coordination sequence T1 for Cordierite.at n=25A008251
- Molien series for alternating group Alt_12 (or A_12).at n=25A008635
- Number of partitions of n into at most 12 parts.at n=25A008641
- Coordination sequence T7 for Zeolite Code CON.at n=29A009874
- Coordination sequence T2 for Zeolite Code VET.at n=25A009903
- Coordination sequence T2 for Zeolite Code VNI.at n=25A009908
- a(n) = floor(n*(n-1)*(n-2)/13).at n=29A011895
- Expansion of 1/(1-x^9-x^10-x^11-x^12-x^13-x^14-x^15-x^16-x^17).at n=56A017884
- Expansion of 1/(1 - x^9 - x^10 - ...).at n=52A017903
- Sum(C(j)*(n-j)*4^(n-j-1),j=0..n-1), C = Catalan numbers.at n=5A018218
- Number of cyclic oriented multigraphs on n labeled arcs (without loops).at n=4A020564
- Fibonacci sequence beginning 2, 6.at n=13A022112
- Numbers k such that Fibonacci(k) == 8 (mod k).at n=16A023177