6569
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
- 2
- Divisor Sum
- 6570
- Proper Divisor Sum (Aliquot Sum)
- 1
- 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
- 6568
- Möbius Function
- -1
- Radical
- 6569
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- 212
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- yes
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 849
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes p such that the multiplicative order of 2 modulo p is (p-1)/4.at n=39A001134
- Numbers that are the sum of 11 positive 7th powers.at n=33A003378
- Numbers that are the sum of 9 nonzero 8th powers.at n=10A003387
- Primes of the form 2^a + 3^b.at n=44A004051
- Primorial -1 primes: primes p such that -1 + product of primes up to p is prime.at n=15A006794
- Numbers k such that the continued fraction for sqrt(k) has period 55.at n=6A020394
- a(n) is the smallest number that is the sum of 3 nonzero squares in exactly n ways.at n=32A025414
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 12.at n=4A031600
- Primes that are concatenations of k with k + 4.at n=9A032627
- Sum of first n primes of form 4k-1.at n=38A038347
- Numerators of continued fraction convergents to sqrt(908).at n=4A042754
- Numbers having three 0's in base 9.at n=15A043455
- Numbers whose base-4 representation contains exactly three 1's and four 2's.at n=8A045104
- p, p+8 and p+12 are primes.at n=38A046141
- Primes p such that p+2 and p+8 are also primes but p+6 is not.at n=37A049437
- Erroneous version of A006794.at n=14A055511
- Primes p such that x^24 = 2 has no solution mod p, but x^12 = 2 has a solution mod p.at n=33A059331
- Primes p such that x^56 = 2 has no solution mod p, but x^28 = 2 has a solution mod p.at n=40A059635
- Lesser of irregular twin primes.at n=21A060012
- Primes p that have exactly three primitive roots that are not primitive roots mod p^2.at n=1A060519