9481
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 10000
- Proper Divisor Sum (Aliquot Sum)
- 519
- 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
- 8964
- Möbius Function
- 1
- Radical
- 9481
- 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
- 153
- 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
- no
- Odd
- yes
Appears in sequences
- a(n) = n^2 written backwards.at n=42A002942
- Expansion of 1/((1-x)*(1-2*x)*(1-9*x)).at n=4A016204
- Numbers whose sum of divisors is a fourth power.at n=18A019422
- a(n) = least m such that if r and s in {1/1, 1/3, 1/5, ..., 1/(2n-1)} satisfy r < s, then r < k/m < (k+2)/m < s for some integer k.at n=42A024841
- a(n) = (d(n)-r(n))/2, where d = A026066 and r is the periodic sequence with fundamental period (1,0,0,0).at n=36A026067
- Poincaré (or Molien) series for ring of Siegel modular forms of genus 3 (associated with full modular group Gamma_3).at n=45A027634
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 48 ones.at n=33A031816
- Numbers whose set of base-13 digits is {1,4}.at n=27A032825
- a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 4, where m = 2*n - 2 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1 and a(2) = a(3) = 3.at n=16A049927
- a(n) = T(n,n-5), array T as in A055807.at n=16A055810
- Squares of 1 and primes, written backwards.at n=14A060998
- Composite numbers whose divisors (except 1) all contain the digit 9.at n=15A062680
- n^2 read backwards, for n = 51, 50, 49, ..., 1.at n=8A080334
- Odd squares written backwards and sorted.at n=43A107313
- Semiprimes whose digit reversal is a nontrivial power.at n=25A108849
- a(n) is the largest number m such that sigma(m)=10^n, or if there is no such m a(n)=0.at n=4A110076
- Number of squares in an n X n grid of squares with diagonals.at n=20A111500
- Semiprimes (A001358) whose digit reversal is a powerful(1) number (A001694).at n=31A115688
- Semiprimes (A001358) whose digit reversal is a square.at n=21A115710
- Start with 1 and repeatedly reverse the digits and add 48 to get the next term.at n=13A118160