2126
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 11
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 3192
- Proper Divisor Sum (Aliquot Sum)
- 1066
- 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
- 1062
- Möbius Function
- 1
- Radical
- 2126
- 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
- 76
- 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
- Number of nonequivalent dissections of a polygon into n pentagons by nonintersecting diagonals rooted at a cell up to rotation.at n=5A005037
- Coordination sequence T5 for Zeolite Code HEU.at n=30A008120
- Coordination sequence T3 for Zeolite Code LIO.at n=32A008131
- Molien series for cyclic group of order 5.at n=20A008646
- Number of 3 X 3 symmetric stochastic matrices under row and column permutations.at n=50A008764
- Coordination sequence T5 for Zeolite Code CGF.at n=32A019455
- Coordination sequence T4 for Zeolite Code SAO.at n=36A019574
- Numbers k such that the continued fraction for sqrt(k) has period 36.at n=24A020375
- a(n) = position of 5 + n^2 in A004432.at n=49A024808
- Self-convolution of array T given by A026692.at n=6A026991
- a(n) = Sum_{k=0..m} (k+1) * A026022(n, k), where m=n for n=0,1 and m = floor((n+3)/2) for n >= 2.at n=9A027298
- Numbers k such that k*(k+3) is a palindrome.at n=9A028553
- 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 46.at n=1A031544
- "DGK" (bracelet, element, unlabeled) transform of 1,2,3,4,...at n=13A032233
- Concatenation of n and n + 5 or {n,n+5}.at n=20A032610
- a(n) = 2*a(n-1) + a(floor(n/2)), with a(1) = 1, a(2) = 2.at n=10A033490
- Triangular array associated with Schroeder numbers.at n=33A033878
- Fractional part of square root of a(n) starts with 1: first term of runs.at n=43A034107
- Limit of the position of the n-th partition into parts 5k+2 or 5k+3 in the list of all integer partitions sorted in reverse lexicographic order, for integers == 2 (mod 5).at n=46A035407
- Limit of the position of the n-th partition into parts 5k+2 or 5k+3 in the list of all integer partitions sorted in reverse lexicographic order, for integers == 3 (mod 5).at n=35A035408