3005
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 8
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 3612
- Proper Divisor Sum (Aliquot Sum)
- 607
- 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
- 2400
- Möbius Function
- 1
- Radical
- 3005
- 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
- 141
- 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
- Worst case of a Jacobi symbol algorithm.at n=5A005826
- Crystal ball sequence for planar net 3.6.3.6.at n=36A008580
- Coordination sequence T2 for Zeolite Code RUT.at n=36A009898
- Expansion of x/(1 - 7*x - 4*x^2).at n=5A015561
- Expansion of Product_{m>=1} (1+q^m)^(-4).at n=20A022599
- n written in fractional base 6/3.at n=29A024636
- a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ... + a(n-3)*a(3) for n >= 4, with initial terms 1, -1, 1, 1.at n=21A025258
- Positive numbers having the same set of digits in base 6 and base 7.at n=43A033170
- a(n) = 2*n^2 + 3*n + 3.at n=38A033816
- Multiplicity of highest weight (or singular) vectors associated with character chi_119 of Monster module.at n=41A034507
- Number of partitions of n into parts not of form 4k+2, 16k, 16k+3 or 16k-3.at n=46A036021
- a(n) = n^n - n!.at n=5A036679
- Numbers n such that string 0,5 occurs in the base 10 representation of n but not of n-1.at n=31A044337
- Numbers n such that string 0,5 occurs in the base 10 representation of n but not of n+1.at n=31A044718
- Coordination sequence T3 for Zeolite Code ISV.at n=38A047960
- Becomes prime or 4 after exactly 7 iterations of f(x) = sum of prime factors of x.at n=31A048129
- Number of factorizations with 2 levels of parentheses indexed by prime signatures. A050338(A025487).at n=37A050339
- Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 4.at n=40A051969
- Discriminants of real quadratic fields of ERD-type with class groups of exponent 2 and discriminants of the form D = r^2*k^2+4k, k odd.at n=34A051992
- Let Oc(n) = A005900(n) = n-th octahedral number. Consider all integer triples (i,j,k), j >= k > 0, with Oc(i) = Oc(j)+Oc(k), ordered by increasing i; sequence gives i values.at n=4A053676