6568
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 25
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 12330
- Proper Divisor Sum (Aliquot Sum)
- 5762
- 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
- 3280
- Möbius Function
- 0
- Radical
- 1642
- Omega Function (Ω)
- 4
- 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
- 31
- 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
- Numbers that are the sum of 10 positive 7th powers.at n=30A003377
- Numbers that are the sum of 8 nonzero 8th powers.at n=9A003386
- a(n) = ceiling(n*phi^11), where phi is the golden ratio, A001622.at n=33A004966
- From a problem concerning circulant matrices and Gauss sums.at n=9A007792
- a(n) = [ a(n-1)/a(1) + a(n-3)/a(3) + a(n-5)/a(5) + ... ], for n >= 3.at n=23A022859
- 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 39.at n=30A031537
- Numbers n such that there are equal numbers of 0's and 1's in first n digits of binary representation of Pi.at n=30A039624
- Numbers having three 0's in base 9.at n=14A043455
- Numbers whose base-5 representation contains exactly three 2's and two 3's.at n=20A045276
- a(n) = Sum_{i=0..n} T(i,n-i) where T is A049627.at n=39A049628
- a(n) = 3^(2*n) + 7.at n=4A062508
- Smallest member of triple of consecutive numbers each of which is the sum of two different nonzero squares.at n=34A064715
- Smallest member of three consecutive numbers each of which is the sum of two nonzero squares (not necessarily different).at n=40A064716
- Lesser of three consecutive nonsquare integers each of which is the sum of two squares.at n=33A073412
- Number of isolated-pentagon fullerenes with 2n vertices (or carbon atoms).at n=26A086423
- Numbers k such that numerator(Bernoulli(2*k)/(2*k)) is different from numerator(Bernoulli(2*k)/(2*k*(2*k-1))).at n=25A090495
- Least k such that k*(Mersenne_prime(n)^2) + 1 is prime.at n=15A098819
- Expansion of (sqrt(1+2x) + sqrt(1-2x))/(2*(1-2x)^(3/2)).at n=11A099325
- Positive integers n such that n^11 + 1 is semiprime.at n=33A105122
- Triangle read by rows: T(n,k) is number of paths from (0,0) to (3n,0) that stay in the first quadrant (but may touch the horizontal axis), consisting of steps u=(2,1), U=(1,2), or d=(1,-1) and having abscissa of the first peak equal to k.at n=32A108438