6438
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 13680
- Proper Divisor Sum (Aliquot Sum)
- 7242
- 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
- 2016
- Möbius Function
- 1
- Radical
- 6438
- Omega Function (Ω)
- 4
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 75
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- Number of increasing sequences of star chain type with maximal element n.at n=16A008927
- Numbers having period-2 6-digitized sequences.at n=20A031357
- Number of partitions in parts not of the form 25k, 25k+3 or 25k-3. Also number of partitions with at most 2 parts of size 1 and differences between parts at distance 11 are greater than 1.at n=34A036002
- Sum of the first n palindromes (A002113).at n=43A046489
- McKay-Thompson series of class 20E for Monster.at n=19A058554
- a(n) = Sum_{d|n} sigma(n*d).at n=44A069546
- a(0) = 2 and, for n >= 1, rewrite 0->100 in the binary expansion of n and append 10 to the right.at n=17A080310
- Numbers k such that numerator(Bernoulli(2*k)/(2*k)) is different from numerator(Bernoulli(2*k)/(2*k*(2*k-1))).at n=24A090495
- a(n) = Sum_{i+j+k=n, 0<=j<=i<=n, 0<=k<=n} (n+k)!/(i! * j! * (2*k)!).at n=7A092465
- Least multiple of n such that every partial concatenation followed by a 9 is prime.at n=36A105185
- Largest member z of a triple 0<x<y<z such that z^2-y^2, z^2-x^2 and y^2-x^2 are perfect squares.at n=35A111105
- a(n) = n*(n+7)*(n+8)/6.at n=29A111396
- Index of smallest prime number where n consecutive leading digits of the index match n consecutive leading digits in the prime.at n=2A133583
- Pairs (j, k) of numbers j<k such that phi(j) = phi(k), sigma(j) = sigma(k), d(j) = d(k).at n=19A134922
- Number of sequences of length n over {1, -1} with Erdős discrepancy <= 2.at n=20A181740
- Number of nX3 binary arrays with no element equal to the sum mod 3 of its horizontal and vertical neighbors.at n=8A183365
- T(n,k)=Number of nXk binary arrays with no element equal to the sum mod 3 of its horizontal and vertical neighbors.at n=57A183368
- The number of different classes of 2-dimensional convex lattice polytopes having volume n/2 up to unimodular equivalence.at n=34A187015
- Inverse permutation to A190130.at n=18A190131
- Number of 4X2 integer matrices with each row summing to zero, row elements in nondecreasing order, rows in lexicographically nondecreasing order, and the sum of squares of the elements <= 2*n^2 (number of collections of 4 zero-sum 2-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations).at n=23A192703