8657
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
- 4
- Divisor Sum
- 9456
- Proper Divisor Sum (Aliquot Sum)
- 799
- 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
- 7860
- Möbius Function
- 1
- Radical
- 8657
- 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
- 140
- 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) = a(n-1) + a(n-4) with a(0) = 0, a(1) = a(2) = a(3) = 1.at n=31A003269
- Expansion of (1-x)/(1-x-x^4).at n=34A017898
- Consider the Diophantine equation x^3 + y^3 = z^3 + 1 (1 < x < y < z) or 'Fermat near misses'. Sequence gives values of z in monotonic increasing order.at n=13A050791
- Expansion of (1-x)*(1+x)/(1-x-2*x^2+x^4).at n=15A052535
- a(n) = floor(A*a(n-1) + B*a(n-2) + C)/p^r, where p^r is the highest power of p dividing floor(A*a(n-1) + B*a(n-2) + C), A=1.0001, B=1.0001, C=1, p=2.at n=21A053521
- a(n) is its own 4th difference.at n=7A055990
- Non-palindromic numbers such that the two largest proper divisors are palindromes having at least two digits and no other divisor is a palindrome with at least two digits.at n=14A074889
- Number of permutations of {1,2,...,n} containing exactly 3 occurrences of the 132 pattern.at n=5A082971
- Incorrect version of A082971.at n=3A082972
- Expansion of -x - x^3*(2 -2*x^4 +x^5)/((1-x^2)*(1+x+x^4)).at n=29A089076
- A trisection of 1/(1-x-x^4).at n=10A099234
- Sum C(n-3k,k-1), k=0..floor(n/4).at n=33A099561
- a(n) = a(n - 2) + a(n - 8), with a(1) = ... = a(8) = 1.at n=60A122522
- a(n) = a(n - 2) + a(n - 8), with a(1) = ... = a(8) = 1.at n=61A122522
- Numbers k for which 8*k+1, 8*k+3 and 8*k+7 are primes.at n=43A123978
- Number of (19,14)-reverse multiples with n digits.at n=71A226517
- Semiprimes whose reversal + 1 is a square.at n=14A245362
- Numbers k with the property that it is possible to write the base 2 expansion of k as concat(a_2,b_2), with a_2>0 and b_2>0 such that, converting a_2 and b_2 to base 10 as a and b, we have sigma(a) + sigma (b) = sigma(k) - k.at n=23A258813
- Integer c such that (a^3 + b^3 - c^3)^2 = 1 where a,b,c are integers greater than 2.at n=28A281224
- Number T(n,k) of self-avoiding planar walks of length k starting at (0,0), ending at (n,0), remaining in the first quadrant and using steps (0,1), (1,0), (1,1), (-1,1), and (1,-1) with the restriction that (0,1) is never used below the diagonal and (1,0) is never used above the diagonal; triangle T(n,k), k>=0, floor((sqrt(1+8*k)-1)/2)<=n<=k, read by columns.at n=55A284652