6547
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
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 6548
- 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
- 6546
- Möbius Function
- -1
- Radical
- 6547
- 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
- 137
- 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
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 845
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- a(n) = floor( n*(n-1)*(n-2)/5 ).at n=33A011887
- Numbers k such that the continued fraction for sqrt(k) has period 94.at n=9A020433
- Initial members of prime triples (p, p+4, p+6).at n=46A022005
- Ordered sequence of distinct terms of the form floor(x^i * floor(x^j)), i,j >= 0, where x = sqrt(3).at n=43A022769
- 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 79.at n=30A031577
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 38 ones.at n=35A031806
- Upper prime of a difference of 18 between consecutive primes.at n=24A031937
- Discriminants of imaginary quadratic fields with class number 11 (negated).at n=25A046008
- Primes p such that p+4 and p+16 are also primes.at n=44A049492
- Primes at which the difference pattern X42Y (X and Y >= 6) occurs in A001223.at n=17A052164
- 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=27A053521
- Local ranks of terms of A057122.at n=38A057124
- Primes p that have exactly two primitive roots that are not primitive roots mod p^2.at n=29A060518
- Primes with 2 representations: p*q*r - 1 = u*v*w + 1 where p, q, r, u, v and w are primes.at n=23A063644
- Consider sequence of fractions A066657/A066658 produced by ratios of terms in A066720; let m = smallest integer such that all fractions 1/n, 2/n, ..., (n-1)/n have appeared when we reach A066720(m) = k; sequence gives values of m; set a(n) = -1 if some fraction i/n never appears.at n=9A066849
- Number of binary arrangements on n X n array without adjacent three 1's.at n=4A067968
- Primes whose digits can be arranged in increasing cyclic order - to form a substring of 123456789012345678901234567890...at n=21A068710
- Primes containing 2k digits in which the sum of the first k digits is that of the last k digits.at n=41A068896
- Suppose p and q = p+22 are primes. Define the difference pattern of (p,q) to be the successive differences of the primes in the range p to q. There are 51 possible difference patterns, shown in the Comments line. Sequence gives smallest value of p for each difference pattern, sorted by magnitude.at n=47A079021
- Primes p such that both p-1 and p+1 have at most 3 prime factors, counted with multiplicity; i.e., primes p such that bigomega(p-1) <= 3 and bigomega(p+1) <= 3, where bigomega(n) = A001222(n).at n=29A079153