2186
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 3282
- Proper Divisor Sum (Aliquot Sum)
- 1096
- 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
- 1092
- Möbius Function
- 1
- Radical
- 2186
- 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
- 32
- 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 k such that phi(k) = phi(k+2).at n=36A001494
- Coordination sequence T2 for Zeolite Code MEL.at n=30A008151
- Coordination sequence T1 for Zeolite Code VFI.at n=36A008245
- If a, b in sequence, so is ab+6.at n=26A009307
- Coordination sequence for sigma-CrFe, Position Xd.at n=12A009959
- exp(arctan(x)*exp(x))=1+x+3/2!*x^2+8/3!*x^3+25/4!*x^4+100/5!*x^5...at n=7A012408
- a(n) = n^2 - floor( n/2 ).at n=47A014848
- Number of ordered triples of integers from [ 1,n ] with no common factors between pairs.at n=35A015632
- Numbers k such that the continued fraction for sqrt(k) has period 19.at n=16A020358
- Plaindromes: numbers whose digits in base 3 are in nondecreasing order.at n=35A023745
- a(n) = 3^n - 1.at n=7A024023
- a(n) = (1/C(0,0) + 1/C(2,1) + ... + 1/C(2n,n))*L, where L = LCM{C(0,0), C(2,1),..., C(2n,n)}.at n=5A025541
- a(n) = (d(n)-r(n))/2, where d = A026037 and r is the periodic sequence with fundamental period (1,0,0,1).at n=21A026038
- Coordination sequence T4 for Zeolite Code ITE.at n=32A027372
- a(i)=a(i-1)+a(j_1)*a(j_2) {where j_1+j_2=i-1, j_1 <= q j_2} + a(j_1)*a(j_2)*a(j_3) {where j_1+j_2+j_3=i-1, j_1 <= q j_2 <= q j_3} +...+ a(1)^{i-1}.at n=10A027881
- a(n) = Sum_{k=0..2*n-1} T(n, k)*T(n, k+1), T given by A027960.at n=4A027985
- a(n+1) = smallest number not containing any digits of a(n), working in base 3.at n=14A030439
- Write 1,2,... in a clockwise spiral; sequence gives numbers on positive x axis.at n=23A033951
- a(0)=2; a(n) is the smallest k > a(n-1) such that the fractional part of k^(1/9) starts with n.at n=35A034074
- Number of ways to place a non-attacking white and black pawn on n X n chessboard.at n=7A035290