2261
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
- 8
- Divisor Sum
- 2880
- Proper Divisor Sum (Aliquot Sum)
- 619
- 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
- 1728
- Möbius Function
- -1
- Radical
- 2261
- 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
- 19
- 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
- Number of paraffins C_n H_{2n} X_2 with n carbon atoms.at n=9A000636
- Sum of lengths of longest increasing subsequences of all permutations of n elements.at n=5A003316
- Molien series for Weyl group E_7.at n=41A008583
- A B_2 sequence: a(n) = least value such that sequence increases and pairwise sums of distinct elements are all distinct.at n=38A011185
- Orders of cyclotomic polynomials containing a coefficient the absolute value of which is >= 3.at n=23A013591
- Number of triples of different integers from [ 2,n ] with no common factors between pairs.at n=36A015620
- Odd numbers k such that phi(k) | sigma_3(k).at n=38A015809
- Expansion of g.f. 1/((1-2x)(1-3x)(1-5x)).at n=4A016273
- Coordination sequence T4 for Zeolite Code TER.at n=32A016436
- a(n) = n*(23*n + 1)/2.at n=14A022281
- a(n) = n^2 + n + 5.at n=47A027690
- a(n) is the smallest k > a(n-1) such that k^2 has no digit in common with a(n-1)^2.at n=37A030287
- Numbers k such that k^2 contains only digits {1,2,5}.at n=12A031153
- Numbers whose square contains no loops in its digits (assumes 1, 2, 3, 5, 7 have no loops and 0, 4, 6, 8, 9 do).at n=32A034905
- Numbers k such that d(i) is a power of 2 for all k <= i <= k+6, where d(i) = number of divisors of i.at n=35A036540
- Numbers k such that string 1,0 occurs in the base 7 representation of k but not of k-1.at n=45A044145
- Numbers k such that string 2,5 occurs in the base 8 representation of k but not of k-1.at n=40A044208
- Numbers k such that the string 8,2 occurs in the base 9 representation of k but not of k-1.at n=30A044325
- Numbers n such that string 6,1 occurs in the base 10 representation of n but not of n-1.at n=24A044393
- Numbers n such that string 2,5 occurs in the base 8 representation of n but not of n+1.at n=40A044589