2104
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 7
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 3960
- Proper Divisor Sum (Aliquot Sum)
- 1856
- 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
- 1048
- Möbius Function
- 0
- Radical
- 526
- Omega Function (Ω)
- 4
- 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
- 81
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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 switching networks with C(2,n) acting on the domain and AG(3,2) acting on the domain.at n=2A000884
- Number of unsensed planar maps with n edges and without faces or vertices of degree 1.at n=9A006397
- Number of intransitive (or alternating, or Stanley) trees: vertices are [0,n] and for no i<j<k are both (i,j) and (j,k) edges.at n=6A007889
- Coordination sequence T3 for Zeolite Code AFS and BPH.at n=35A008025
- Coordination sequence for diamond.at n=29A008253
- Number of partitions of n into at most 8 parts.at n=29A008637
- Coordination sequence T1 for Zeolite Code AHT.at n=31A009866
- Coordination sequence T1 for Zeolite Code iRON.at n=32A009881
- Coordination sequence for CaF2(2), F position.at n=29A009925
- Numbers k such that phi(k) + 9 | sigma(k + 9).at n=24A015788
- Squares on infinite chessboard at n moves from center using a {2,3} fairy knight.at n=32A018839
- Numbers k such that the continued fraction for sqrt(k) has period 44.at n=15A020383
- Ordered sequence of distinct terms of the form floor(x^i * floor(x^j)), i,j >= 0, where x = sqrt(3).at n=31A022769
- Number of partitions of n into 8 unordered relatively prime parts.at n=29A023028
- Positive numbers k such that k and 2*k are anagrams in base 8 (written in base 8).at n=7A023073
- Numbers k such that Fib(k) == -21 (mod k).at n=23A023168
- Generalized Catalan Numbers x^2*A(x)^2 -(1-x+x^2+x^3+x^4+x^5+x^6)*A(x) + 1 =0.at n=17A023423
- a(n) = 1*t(n) + 2*t(n-1) + ... + k*t(n+1-k), where k=floor((n+1)/2) and t = A002808 (composite numbers).at n=23A023863
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers), t = (composite numbers).at n=22A024860
- Number of partitions of n in which the greatest part is 8.at n=37A026814