6667
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 25
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 6840
- Proper Divisor Sum (Aliquot Sum)
- 173
- 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
- 6496
- Möbius Function
- 1
- Radical
- 6667
- Omega Function (Ω)
- 2
- 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
- 181
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- Number of 3-connected self-dual planar graphs with 2n edges.at n=9A002841
- Expansion of e.g.f.: exp(x + sin(x)).at n=11A009282
- Integer part of ((4th elementary symmetric function of 1,2,..,n)/(2nd elementary symmetric function of 1,2,...,n)).at n=23A024173
- a(n)=Sum{T(n,k)*T(n,k+2)}, 0<=k<=2n-2, T given by A027926.at n=5A027996
- Numbers whose square has its digits in nondecreasing order.at n=41A028819
- Pair up the numbers.at n=33A030656
- 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 81.at n=9A031579
- Lucky numbers that are decimal concatenations of n with n + 1.at n=9A032651
- a(n)^2 is smallest square starting with a string of n 4's.at n=3A034984
- "DIK" (bracelet, indistinct, unlabeled) transform of A000237.at n=9A035349
- Numbers having three 6's in base 10.at n=24A043515
- Numbers whose base-9 representation has exactly 5 runs.at n=14A043634
- a(n)=Sum{T(n,j): j=1,2,...,n}, array T given by A048201.at n=20A048209
- Find smallest pair (x,y) such that x^2-y^2 = 11...1 (n times) = (10^n-1)/9; sequence gives value of y.at n=11A048612
- Beastly (or hateful) numbers: numbers containing the string 666 in their decimal expansion.at n=13A051003
- Periodic points under the map A053392 that adds consecutive pairs of digits and concatenates them.at n=22A053393
- Numbers k such that k^2 contains only digits {4,8,9}.at n=8A053966
- (n - phi(n)) | sigma(n) for composite n not congruent to 2 (mod 4).at n=20A055164
- Number of Fibonacci numbers A000045(k), k <= 10^n, which end in 4.at n=5A067275
- Write 0, 1, ..., n in binary and add as if they were decimal numbers.at n=13A067894