9218
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 15120
- Proper Divisor Sum (Aliquot Sum)
- 5902
- 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
- 4180
- Möbius Function
- -1
- Radical
- 9218
- 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
- 47
- 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
- yes
- Odd
- no
Appears in sequences
- Numbers that are the sum of 11 positive 10th powers.at n=9A004811
- a(0) = 1, a(n) = 9*n^2 + 2 for n>0.at n=32A010002
- Coordination sequence for C_3 lattice: a(n) = 16*n^2 + 2 (n>0), a(0)=1.at n=24A010006
- a(n) = 2nd elementary symmetric function of the first n+1 odd positive integers.at n=10A024196
- dot_product(n,n-1,...2,1)*(7,8,...,n,1,2,3,4,5,6).at n=26A026066
- 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 96.at n=0A031594
- Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 96.at n=1A031774
- Trajectory of 7 under map x --> x + (x-with-digits-reversed).at n=9A033650
- Trajectory of 19 under map x->x + (x-with-digits-reversed).at n=7A033655
- Trajectory of 23 under map x->x + (x-with-digits-reversed).at n=8A033657
- Trajectory of 29 under map x->x + (x-with-digits-reversed).at n=6A033660
- Trajectory of 89 under map x->x + (x-with-digits-reversed).at n=4A033670
- T(n,n-3), array T as in A038792.at n=38A038793
- a(n) = (n-1)*2^n + 2.at n=10A048495
- a(n) = 4^n + 7^n + 9^n.at n=4A074569
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 0, 1), (0, 1, -1), (0, 1, 1), (1, -1, -1)}.at n=9A148621
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (0, 1, -1), (0, 1, 0), (1, 0, -1), (1, 1, 0)}.at n=8A149943
- Numbers k such that the string k is found at position k-4 in the decimal digits of Pi.at n=3A153223
- Number of reduced words of length n in the Weyl group B_10.at n=7A161755
- Number of reduced words of length n in the Weyl group D_10.at n=7A162248