6646
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 9972
- Proper Divisor Sum (Aliquot Sum)
- 3326
- 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
- 3322
- Möbius Function
- 1
- Radical
- 6646
- 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
- 119
- 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
- yes
- Odd
- no
Appears in sequences
- Coordination sequence for FeS2-Marcasite, S position.at n=40A009954
- Expansion of Product_{m>=1} (1+q^m)^(4*m).at n=8A027906
- 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 80.at n=15A031578
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 52 ones.at n=12A031820
- Increasing gaps among twin primes: size.at n=37A036063
- Numbers having three 6's in base 10.at n=16A043515
- Numbers whose base-9 representation has exactly 5 runs.at n=3A043634
- Decimal concatenations of the quadruples (d1,d2,d3,d4) with elements in {2,4,6} for which there exists a prime p >= 5 such that the differences between the 5 consecutive primes starting with p are (d1,d2,d3,d4).at n=23A078868
- Near-repdigit semiprimes with 6 as repeated digit.at n=13A105987
- Semiprimes with semiprime digits (digits 4, 6, 9 only).at n=23A107342
- Expansion of 2/(3-sqrt(3-2*sqrt(1-4x))).at n=10A112520
- a(0)=1; for n > 0, a(n) = a(n-1) + a(prime(n)(mod n)), where prime(n) is the n-th prime.at n=36A127066
- Numbers k such that k and k^2 use only the digits 1, 3, 4, 6 and 9.at n=20A137027
- Even composites in A145832.at n=38A145915
- a(n) = 289*n - 1.at n=22A158253
- a(n) is the smallest term m in A173978 for which A020639(2m-3) = prime(n), n > 1.at n=23A173980
- Number of Dyck n-paths all of whose ascents have lengths equal to 1 (mod 6).at n=15A212386
- Smallest k such that A002522(k) and A002522(k+2n) are successive primes of the form m^2+1.at n=28A245463
- A specially constructed B_2 sequence with sum of reciprocals greater than that of the Mian-Chowla sequence A005282.at n=56A259964
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 878", based on the 5-celled von Neumann neighborhood.at n=25A273741