6523
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 7128
- Proper Divisor Sum (Aliquot Sum)
- 605
- 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
- 5920
- Möbius Function
- 1
- Radical
- 6523
- 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
- 199
- 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) = n*(27*n - 1)/2.at n=22A022284
- a(n) = (d(n)-r(n))/5, where d = A026040 and r is the periodic sequence with fundamental period (4,0,4,3,4).at n=43A026042
- 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=29A031577
- Lucky numbers with size of gaps equal to 18 (upper terms).at n=39A031901
- a(n)^2 is a square whose digits occur with an equal minimum frequency of 2.at n=22A052049
- Semiprimes p1*p2 such that p2 mod p1 = 10, with p2 > p1.at n=37A064908
- a(n) = (1/3)*n^3 - n^2 - (1/3)*n - 1.at n=28A109620
- Sequence is {a(5,n)}, where a(m,n) is defined at sequence A111518.at n=11A111523
- Numbers m such that (15m-4, 15m-2, 15m+2, 15m+4) is a prime quadruple.at n=35A112540
- Numbers n such that 9n^2 is a zeroless pandigital number.at n=9A162859
- a(n) = (A212146(n)-1)/2.at n=17A212147
- Partial sums of A253086.at n=39A255150
- Numbers n such that n*2^607 - 1 is prime.at n=27A265499
- The number of partitions of n which represent Chomp positions with Sprague-Grundy value 6.at n=50A284693
- Numbers k such that (58*10^k + 329)/9 is prime.at n=18A294570
- Number of n X 3 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1 neighboring 1.at n=8A297390
- Number A(n,k) of tilings of a k X n rectangle using V (2m+1)-ominoes (m >= 0) in standard orientation; square array A(n,k), n>=0, k>=0, read by antidiagonals.at n=71A322494
- Number A(n,k) of tilings of a k X n rectangle using V (2m+1)-ominoes (m >= 0) in standard orientation; square array A(n,k), n>=0, k>=0, read by antidiagonals.at n=72A322494
- Number of tilings of a 5 X n rectangle using V (2m+1)-ominoes (m >= 0) in standard orientation.at n=6A322498
- Number of tilings of a 6 X n rectangle using V (2m+1)-ominoes (m >= 0) in standard orientation.at n=5A322499