6420
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 18144
- Proper Divisor Sum (Aliquot Sum)
- 11724
- 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
- 1696
- Möbius Function
- 0
- Radical
- 3210
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 4
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
- 23
- 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
- Cycle class sequence c(2n) (the number of true cycles of length 2n in which a certain node is included) for zeolite AFS = MAPSO-46 starting with a T2 atom.at n=5A018966
- Cycle class sequence c(2n) (the number of true cycles of length 2n in which a certain node is included) for zeolite BPH = Beryllophosphate-H Na7K7[Be14P14O56].20H2O starting with a T2 atom.at n=5A018996
- Number of balls in pyramid with base either a regular hexagon or a hexagon with alternate sides differing by 1 (balls in hexagonal pyramid of height n taken from hexagonal close-packing).at n=29A019298
- n written in fractional base 8/6.at n=24A024648
- Size of lexicographic code of length n, Hamming distance 8 and weight 8.at n=38A030069
- Least term in period of continued fraction for sqrt(n) is 8.at n=21A031432
- Numbers k such that A174141(k) is divisible by k.at n=33A032581
- Bisection of A028289.at n=42A038390
- T(n, k) = S(2*n + 1, n, k + 1) for 0<=k<=n and n >= 0, array S as in A050157.at n=33A050158
- T(n,k) = S(2n-1,n-1,k-1), 0<=k<=n, n >= 0, array S as in A050157.at n=42A050159
- Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,9.at n=11A064241
- Numbers k such that S(k+2) = d(k)+2, where S(k) is the Kempner function (A002034) and d(k) is the number of divisors of k (A000005).at n=34A073535
- a(1)=1, a(n)=2a(n-1)+1 if a(n-1) is prime, a(n)=a(n-1)+1 otherwise.at n=43A083005
- Successively larger 3-ball ground-state site swaps of A084501 in concatenated decimal notation.at n=32A084502
- Successively larger 3-ball indecomposable ground-state site swaps of A084511 in concatenated decimal notation.at n=17A084512
- Successively larger 3-ball 'prime' ground-state site swaps of A084521 in concatenated decimal notation.at n=16A084522
- The sixth column of triangle A091492, excluding leading zeros.at n=43A091498
- Let f(x)=(largest digit of x)^(smallest digit of x) + x (A097385). Sequence gives numbers n such that f(n) and f(n+1) are both prime.at n=21A097387
- 63-gonal numbers: a(n) = n*(61*n - 59)/2.at n=15A098140
- a(1) = 668; for n > 1, a(n) = a(n-1) + 1 + sum of distinct prime factors of a(n-1) that are < a(n-1).at n=23A105212