6550
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
- 12
- Divisor Sum
- 12276
- Proper Divisor Sum (Aliquot Sum)
- 5726
- 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
- 2600
- Möbius Function
- 0
- Radical
- 1310
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 3
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
- no
- Squarefree Number
- no
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = n*(21*n-1)/2.at n=25A022278
- Expansion of 1/((1-2*x)*(1-5*x)*(1-7*x)*(1-12*x)).at n=3A025996
- Numbers k such that 103*2^k+1 is prime.at n=11A032401
- Increasing gaps among twin primes: size.at n=36A036063
- Numbers whose base-4 representation contains exactly four 1's and three 2's.at n=13A045108
- Numbers whose base-5 representation contains exactly three 0's and three 2's.at n=5A045187
- Numbers n such that 105*2^n-1 is prime.at n=28A050578
- Number of asymmetric mobiles (circular rooted trees) with n nodes and 3 leaves.at n=21A055364
- McKay-Thompson series of class 30D for Monster.at n=31A058615
- McKay-Thompson series of class 35A for Monster.at n=37A058640
- For a number k of length L, let f(k) be the sum of the products of the first i digits of k multiplied by the last L-i digits, for i from 1 to L-1, e.g., f(1234) = 1*234 + 12*34 + 123*4 = 1134. Sequence gives k such that f(k) = k.at n=6A065759
- Expansion of Product_{k>=1} 1/(1 - 2*t^k).at n=11A070933
- Non-palindromic n and its digit reversal have the same sum of prime factors (with repetition).at n=25A085607
- Difference between A007678(2n)/(2n) and (n-1)^2.at n=29A085611
- Number of partitions of n into parts but with two kinds of parts of sizes 1,2,3,4 and 5.at n=17A103924
- Number of partitions of n such that largest part k occurs at most floor(k/2) times.at n=30A118084
- Numbers A141427(k) such that the three numbers A141427(k) -/+ 3 and A141427(k) + 1 are all prime.at n=46A144206
- Number of planar triangular n X n X n nonnegative integer grids with mirror symmetry about one altitude with every similarly oriented 4 X 4 X 4 subtriangle summing to 10.at n=6A154078
- a(n) = Sum_{k=1..n} (k+2)!/k! = Sum_{k=1..n} (k+2)*(k+1).at n=25A180118
- Floor[1/{(3+n^4)^(1/4)}], where {}=fractional part.at n=16A184538