2566
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 3852
- Proper Divisor Sum (Aliquot Sum)
- 1286
- 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
- 1282
- Möbius Function
- 1
- Radical
- 2566
- 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
- 53
- 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
- yes
- Odd
- no
Appears in sequences
- Numbers that are the sum of 5 positive 5th powers.at n=44A003350
- Sum of 11 positive 9th powers.at n=5A004800
- Number of n-dimensional unimodular lattices (or quadratic forms).at n=26A005134
- Coordination sequence T3 for Zeolite Code LTN.at n=35A008142
- Coordination sequence T4 for Zeolite Code MTT.at n=31A008192
- Values of k at which the period of the continued fraction for sqrt(k) sets a new record.at n=31A013645
- Expansion of 1/(1-x^3-x^4-x^5-x^6-x^7).at n=27A017820
- Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite STI = Stilbite Na4Ca8[Al20Si52O144].56H2O starting with a T1 atom.at n=11A019241
- a(n) = [ 1/(2*t(n+1) - t(n) - t(n+2)) ], where t(n) = tan(Pi/2 - 1/n) satisfies n-1 < t(n) < n for all n >= 1.at n=10A024817
- The "semi-Fibonacci numbers": a(n) = A030067(2n - 1), where A030067 is the semi-Fibonacci sequence.at n=55A030068
- 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 50.at n=6A031548
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 46 ones.at n=2A031814
- Numbers with exactly five distinct base-7 digits.at n=12A031984
- Integer part of decimal 'base-2 looking' numbers divided by their actual base-2 values (denominator of a(n) is n, numerator is n written in binary but read in decimal).at n=38A032532
- Trajectory of 1 under map n->27n+1 if n odd, n->n/2 if n even.at n=6A033970
- Positive numbers having the same set of digits in base 5 and base 7.at n=31A037430
- Coordination sequence T5 for Zeolite Code STF.at n=34A038440
- Numerators of continued fraction convergents to sqrt(215).at n=6A041400
- Numerators of continued fraction convergents to sqrt(220).at n=4A041410
- Numbers n such that string 6,1 occurs in the base 9 representation of n but not of n-1.at n=34A044306