9872
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 26
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 10
- Divisor Sum
- 19158
- Proper Divisor Sum (Aliquot Sum)
- 9286
- 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
- 4928
- Möbius Function
- 0
- Radical
- 1234
- Omega Function (Ω)
- 5
- 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
- 135
- 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
- n written in fractional base 10/9.at n=32A024664
- a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 4, where m = n - 1 - 2^p and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = 1 and a(3) = 4.at n=14A049898
- Number of 2 X 2 singular integer matrices with elements from {0,...,n}.at n=35A059306
- Coefficients of polynomials D(n,x) related to median Euler numbers.at n=13A098277
- Partial sums of repdigits of A002282.at n=3A099675
- A Catalan transform of [x^n](1/(1-2x-2x^2)) (A002605).at n=7A155084
- Number of lines through at least 2 points of an 8 X n grid of points.at n=26A160848
- Monotonic ordering of nonnegative differences 10^i-2^j, for 40>= i>=0, j>=0.at n=28A192125
- E.g.f.: Sum_{n>=0} (1/n!) * Product_{k=1..n} tan(k*x).at n=6A193549
- Number of arrays of n+2 integers in -3..3 with sum zero and adjacent elements differing in absolute value.at n=4A202957
- T(n,k)=Number of arrays of n+2 integers in -k..k with sum zero and adjacent elements differing in absolute value.at n=25A202962
- Number of arrays of 7 integers in -n..n with sum zero and adjacent elements differing in absolute value.at n=2A202967
- Triangle of coefficients of polynomials v(n,x) jointly generated with A209819; see the Formula section.at n=52A209820
- Number of nondecreasing sequences of 4 1..n integers with no element dividing the sequence sum.at n=23A212871
- G.f. A(x) satisfies: [x^n] A(x)^((n+1)(n+2)/2) = 0 for n>1 with a(0)=1 and a(1)=2.at n=5A250117
- a(n) is the least integer k such that there are n values of i <= k for which gpf(i^2 + 1) = gpf(k^2 + 1), where gpf(x) is the greatest prime factor of x.at n=20A258840
- Volatile sequence: a(n) = A018227(n)-6.at n=33A271998
- Numbers m such that there exists at least one integer k < m such that m^2+1 and k^2+1 have the same prime factors.at n=13A282092
- Pairs of integers (x, y), such that x^2 + 1 and y^2 + 1, 1 < y < x, have the same distinct prime factors.at n=26A284477
- Number of possible chess games at the end of the n-th ply starting without queens.at n=3A285873