6390
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 16848
- Proper Divisor Sum (Aliquot Sum)
- 10458
- 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
- 1680
- Möbius Function
- 0
- Radical
- 2130
- 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
- 75
- 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(n) = Sum_{i=1..floor((n+2)/4)} a(2i-1)*a(n-2i+1), with a(1)=3, a(2)=1, and a(3)=2.at n=9A024963
- Numbers k such that A174141(k) is divisible by k.at n=32A032581
- Lattices with n labeled elements.at n=6A055512
- Triangle read by rows: T(n,k) is the number of labeled commutative monoids of order n with k idempotents.at n=20A058159
- McKay-Thompson series of class 30B for the Monster group with a(0) = 0.at n=31A058613
- Eighth column (r=7) of FS(5) staircase array A062985.at n=7A062990
- Bessel polynomial {y_n}''(2).at n=4A065945
- Trisection of A007294.at n=31A073471
- Right side of the triangle A075652.at n=45A075649
- Greedy frac multiples of 1/Pi: a(1)=1, Sum_{n>0} frac(a(n)*x) = 1 at x=1/Pi, where "frac(y)" denotes the fractional part of y.at n=24A080142
- Least positive integer multiples of angle x such that their direction cosines form a unit vector: Sum_{k>0} cos(a(k)*x)^2 = 1, where a(1)=1, a(n+1)>a(n) and x=5/4.at n=34A080198
- a(n) = Sum_{k=1..floor(n/2)} H_k * (n-k)!, where H_k = Sum_{j=1..k} 1/j.at n=7A109719
- a(n) = 15 + floor((2 + Sum_{j=1..n-1} a(j))/3).at n=21A120159
- Numbers n where |sinc(n)| decreases monotonically to 0 (where sinc(x)=sin(x)/x).at n=43A131975
- Numbers n that raised to the powers from 1 to k (with k>=1) are multiple of the sum of their digits (n raised to k+1 must not be a multiple). Case k=9.at n=16A135194
- Cumulative sums of A031443.at n=45A145060
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 0, 0), (1, -1, -1), (1, -1, 1), (1, 1, 0)}.at n=8A149145
- a(n) = n*A007504(n)/2 = n*(sum of first n primes)/2.at n=20A156778
- a(n) = 64*n^2 - n.at n=9A157948
- a(n) = 256*n^2 - 2*n.at n=4A158249