6428
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 5
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 11256
- Proper Divisor Sum (Aliquot Sum)
- 4828
- 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
- 3212
- Möbius Function
- 0
- Radical
- 3214
- Omega Function (Ω)
- 3
- 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
- 168
- 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 generalized partition function.at n=15A002600
- Numbers k such that the continued fraction for sqrt(k) has period 56.at n=27A020395
- 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 40.at n=34A031538
- Maximal number of regions into which 4-space can be divided by n hyperspheres.at n=18A059173
- Hexagonal spiral sequence: sequence is written as a hexagonal spiral around a 'dummy' center, each entry is the sum of the row in the previous direction containing the previous entry.at n=19A063178
- Number of subgroups of the group GL(2,Z_n) of invertible 2 X 2 matrices mod n (sequence A000252).at n=10A066514
- a(n) is the action of recursively applying 'Rule 30' elementary cellular automata on the binary representation of n if the cells may only expand into the significant bit, a(0) = 1.at n=12A074890
- Left truncatable 3-almost primes, in which repeatedly deleting the leftmost digit gives a 3-almost prime at every step until a single-digit 3-almost prime remains.at n=40A085248
- Number of meaningful differential operations of the n-th order on the space R^10.at n=11A090995
- Terms in a specific cycle of length 29 of the map x->A098189(x).at n=19A098192
- Integers n such that 8*10^n+21 is prime.at n=14A111022
- a(1)=1. a(n+1) = sum a(k), where the sum is over all positive integers k, k <= n, where each positive integer <= k and coprime to k is also coprime to n.at n=17A124693
- Number of base 8 circular n-digit numbers with adjacent digits differing by 3 or less.at n=5A125318
- A nonsense sequence.at n=37A153637
- A nonsense sequence.at n=43A153637
- Row sums of triangle defined in A113820.at n=18A160968
- Number of symmetry classes of 3 X 3 magilatin squares with positive values < n.at n=15A173729
- Numbers n such that n!8+1 is prime (for n!8 see A114800).at n=37A204661
- Walks of length n on the x-axis using steps {1,0,-1} and visiting no point more than twice.at n=10A212587
- Partial sums of A014817.at n=37A227841