2065
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 2880
- Proper Divisor Sum (Aliquot Sum)
- 815
- 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
- 1392
- Möbius Function
- -1
- Radical
- 2065
- 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
- 125
- 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
- no
- Odd
- yes
Appears in sequences
- Numbers m such that Fibonacci(m) ends with m.at n=42A000350
- Coordination sequence T1 for Zeolite Code FAU.at n=38A008105
- Coordination sequence T1 for Zeolite Code RTE.at n=31A009890
- Coordination sequence T3 for Zeolite Code RTE.at n=31A009892
- Orders of cyclotomic polynomials containing a coefficient the absolute value of which is >= 3.at n=21A013591
- Numbers n such that phi(n) | sigma_7(n).at n=48A015765
- Numbers n such that phi(n + 9) | sigma(n) for n not congruent to 0 (mod 3).at n=35A015849
- Expansion of 1/(1-x^4-x^5-x^6-x^7-x^8-x^9-x^10).at n=31A017832
- Pseudoprimes to base 58.at n=16A020186
- Numbers k such that the continued fraction for sqrt(k) has period 28.at n=37A020367
- a(n) = n*(21*n + 1)/2.at n=14A022279
- Expansion of Product_{m>=1} (1 + m*q^m)^7.at n=5A022635
- Convolution of A001950 and A014306.at n=42A023669
- Sequence satisfies T^2(a)=a, where T is defined below.at n=52A027584
- Negative of numerator of y-coordinate of (2n)*P where P is generator for rational points on curve y^2 + y = x^3 - x.at n=4A028938
- Negative of numerator of y coordinate of n*P where P is the generator [0,0] for rational points on curve y^2+y = x^3-x.at n=9A028942
- Numbers k such that 131*2^k+1 is prime.at n=21A032415
- Numbers k such that 261*2^k+1 is prime.at n=38A032507
- Expansion of (1 + x)/(1 - 2*x - x^2 + x^3).at n=9A033303
- a(0)=1, a(1)=1, a(n) = 3*a(n-1) + a(n-2) + 1.at n=7A033538