6505
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
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 7812
- Proper Divisor Sum (Aliquot Sum)
- 1307
- 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
- 5200
- Möbius Function
- 1
- Radical
- 6505
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 137
- 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) = floor( n*(n-1)*(n-2)/14 ).at n=46A011896
- Expansion of 1/((1-3*x)*(1-8*x)).at n=4A016140
- Number of planar simply-connected polyhexes (or benzenoid hydrocarbons) with n hexagons.at n=8A018190
- Pseudoprimes to base 51.at n=26A020179
- Numbers k such that the continued fraction for sqrt(k) has period 56.at n=28A020395
- Lucky numbers with size of gaps equal to 18 (lower terms).at n=39A031900
- Numbers whose base-4 representation contains exactly four 1's and three 2's.at n=12A045108
- Numbers n such that n through n+4 are divisible by the same number of distinct primes.at n=46A045933
- Partial sums of A001891.at n=12A053808
- Sum of the elements in the primitive subsets of the integers 1 to n.at n=12A087078
- Numbers k such that each of k through k+4 are divisible by exactly two primes.at n=41A088986
- Numbers k such that k + (largest digit of k)! is a square.at n=40A095927
- Number of distinct products i*j*k*l for 1 <= i <= j <= k <= l <= n.at n=27A100437
- Array read by antidiagonals: T(n, k) = ((n+4)^k-(n-1)^k)/5.at n=50A102765
- a(n)= 5*a(n-1) -a(n-2) -a(n-3).at n=8A108143
- Numbers n such that p(10n) is prime, where p(n) is the number of partitions of n.at n=14A114170
- Indices n such that the 3 X 3 matrix with components (row by row) prime(n+k), 0 <= k <= 8, has zero determinant.at n=10A117345
- Smaller of two consecutive lucky numbers with the same digital sum.at n=24A118566
- Recurrence sequence derived from the digits of the square root of 3 after its decimal point.at n=9A120482
- Numbers k whose representation can be split in two parts which can be used as seeds for a Fibonacci-like sequence containing k itself.at n=44A130792