6666
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- yes
- Repdigit
- yes
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 14688
- Proper Divisor Sum (Aliquot Sum)
- 8022
- 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
- 2000
- Möbius Function
- 1
- Radical
- 6666
- 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
- no
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 31
- 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
- Convolved Fibonacci numbers.at n=11A001628
- a(n) = 6*(10^n - 1)/9.at n=4A002280
- Repdigit numbers, or numbers whose digits are all equal.at n=33A010785
- Numbers > 9 with all digits the same.at n=23A014181
- Numbers k such that k | 6^k + 6.at n=11A015892
- Even 9-gonal (or enneagonal) numbers.at n=22A028992
- Numbers whose maximal base-10 run length is 4.at n=5A033285
- a(n) = floor(10^5/n).at n=14A033427
- Fancy primitive repdigit polygonal numbers.at n=14A033704
- Fancy primitive repdigit polygonal numbers (with multiplicity).at n=15A033705
- a(n) = least number not of form [ (a^2+b^2)/n ].at n=18A036574
- Numbers congruent to 2,3,6,11 mod 12 missing from A042944 (conjectured to be finite).at n=31A042945
- Base-10 palindromes that start with 6.at n=18A043041
- Numbers having four 6's in base 10.at n=0A043516
- Numbers whose base-9 representation has exactly 5 runs.at n=13A043634
- Catafusenes (see reference for precise definition).at n=9A044047
- Numbers whose base-4 representation contains exactly two 0's and four 2's.at n=19A045051
- Palindromes that are divisible by 6.at n=24A045641
- Palindromic even lucky numbers.at n=20A045960
- Largest palindromic substring in n! without an initial zero.at n=35A046276