6557
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 6720
- Proper Divisor Sum (Aliquot Sum)
- 163
- 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
- 6396
- Möbius Function
- 1
- Radical
- 6557
- 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
- 106
- 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) = (6*n+1)*(6*n+5).at n=13A001513
- Products of 2 successive primes.at n=21A006094
- Ordered sequence of distinct terms of the form floor(x^i * floor(x^j)), i,j >= 0, where x = sqrt(3).at n=44A022769
- a(n) = 9^n - n.at n=4A024102
- a(n)/1000 gives sqrt(n) to 3 places after the decimal point.at n=42A027662
- a(1) = 6; for n > 1, a(n) = product of next 2 primes after a(n-1).at n=2A030641
- [ exp(5/19)*n! ].at n=6A030873
- Squares of primes or products of pairs of consecutive primes.at n=43A033476
- Base-6 palindromes that start with 5.at n=16A043014
- Numbers having three 8's in base 9.at n=29A043487
- Numbers whose base-3 representation contains no 0's and exactly one 1.at n=34A044966
- Numerators of b(n) = (1/16^n)*(4/(8*n+1) - 2/(8*n+4) - 1/(8*n+5) - 1/(8*n+6)).at n=28A048581
- Numbers k such that k^2 contains only digits {2,4,9}.at n=9A053924
- Numerator sequence of mean length of certain stackings of n+1 squares on a double staircase.at n=12A055245
- a(1)=2, a(n+1) is the smallest integer > a(n) such that the smallest prime factor of a(n+1) is the largest prime factor of a(n).at n=44A057602
- Numbers n such that phi(3n-1) = sigma(n).at n=37A067232
- a(n) = (2*n+5)*(2*n+1).at n=39A078371
- Numbers n such that when the digits of Fibonacci(n) are sorted into decreasing order and zeros are dropped it is a prime.at n=45A082922
- a(n) = (4*n+3)*(4*n+7).at n=19A085027
- Numbers that are products of (at least two) consecutive primes.at n=31A097889