8172
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 18
- Divisor Sum
- 20748
- Proper Divisor Sum (Aliquot Sum)
- 12576
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2712
- Möbius Function
- 0
- Radical
- 1362
- Omega Function (Ω)
- 5
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 158
- 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 partitions of 3n-1 into n nonnegative integers each no more than 6.at n=22A001978
- (s(n)+2)/10, where s(n)=n-th base 10 palindrome that starts with 8.at n=39A043087
- Least nontrivial multiple of the n-th prime beginning with 8.at n=48A078292
- a(n) is the difference between the largest and smallest integer solutions to n=x/pi(x), where pi(x) = A000720(x).at n=16A087236
- a(n) is the smallest number m such that for the n-digit number s=10^(n-1)+ m, 10*s+1, 10*s+3, 10*s+7 and 10*s+9 are primes.at n=20A097639
- G.f.: (x - 1)/(x^5 - x^3 - x^2 - x - 1).at n=59A115412
- Numbers k such that k + sigma(k) is a triangular number.at n=36A115904
- 10th-order Fibonacci numbers: a(n+1) = a(n)+...+a(n-9) with a(0) = ... = a(8) = 0, a(9) = 1.at n=23A122265
- Number of 2 X 2 singular integer matrices with entries from {2,...,n}.at n=44A134978
- Y values of the complete set of 23 integer solutions to the Ochoa curve equation.at n=5A141145
- 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, 1), (1, 0, -1), (1, 1, 0)}.at n=7A150542
- Number of 7 X 7 arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to n.at n=17A156392
- Number of n X n arrays of squares of integers, symmetric about both diagonal and antidiagonal, with all rows summing to 17.at n=5A156467
- If an array is made of columns of -nacci sequences (Fibonacci, tribonacci, etc.), all starting with 1,1,2,..., the NW-to-SE diagonals can be extended by computation. This sequence is diagonal 6. See A159741 for details.at n=8A159742
- Unlabeled (cyclic) Motzkin numbers: number of ways of drawing any number of nonintersecting chords joining n unlabeled points equally spaced on a circle, up to rotations of the circle.at n=14A175954
- Number of disconnected regular simple graphs on n vertices with girth exactly 6.at n=38A210716
- Absolute differences between emirps (A006567) and their reversals.at n=57A217591
- a(n) = floor((10*n^3 + 57*n^2 + 102*n + 72) / 72).at n=37A254875
- G.f.: Product_{k>=1} (1+x^k)^(3*k+2).at n=8A255837
- Number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 297", based on the 5-celled von Neumann neighborhood.at n=49A271148