6648
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 16680
- Proper Divisor Sum (Aliquot Sum)
- 10032
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2208
- Möbius Function
- 0
- Radical
- 1662
- Omega Function (Ω)
- 5
- 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
- no
- Harshad Number
- yes
- 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
- Series-parallel numbers.at n=4A000432
- Number of partitions of floor(5n/2)-1 into n nonnegative integers each no more than 5.at n=31A001976
- Number of Hamiltonian paths in K_4 X P_n.at n=2A003772
- a(n) = (n+1)*(n^2+n+2)/2; g.f.: (1 + 2*x^2) / (1 - x)^4.at n=23A006000
- Pisot sequence T(5,9), a(n) = floor(a(n-1)^2/a(n-2)).at n=13A020750
- Convolution of composite numbers and (F(2), F(3), F(4), ...).at n=12A023649
- a(n) = Sum_{k=0..2n-2} T(n,k) * T(n,k+2), with T given by A027113.at n=3A027142
- Triangle of series-parallel numbers.at n=31A036654
- Convolution of natural numbers n >= 1 with Fibonacci numbers F(k), for k >= 5.at n=11A037140
- Numbers whose base-9 representation has exactly 5 runs.at n=5A043634
- a(n)=a(n-1)+a(m), where m=2n-2-2^(p+1) and 2^p<n-1<=2^(p+1), for n >= 4.at n=28A050067
- Digits composite, each digit minus 1 is prime, sum of digits minus 1 is prime, difference of digits (in absolute value) minus 1 is prime.at n=30A058229
- Generalized sum of divisors function: third diagonal of A060047.at n=27A060046
- Multiples of 24 whose digits also sum to 24.at n=19A066270
- Structured tetragonal anti-prism numbers.at n=17A100182
- Number of orbits of the 5-step recursion mod n.at n=45A106287
- Numbers n such that (n+j)^3-(n+j)^2+1 are primes for j=0 to 3.at n=3A111502
- Record gaps between twin primes.at n=37A113274
- Numbers n such that p(5n) is prime, where p(n) is the number of partitions of n.at n=21A114166
- Expansion of phi(-q^9) / phi(-q) in powers of q where phi() is a Ramanujan theta function.at n=20A128770