6138
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
- 3
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 14976
- Proper Divisor Sum (Aliquot Sum)
- 8838
- 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
- 1800
- Möbius Function
- 0
- Radical
- 2046
- 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
- 62
- 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(n) (the number of true cycles of length n in which a certain node is included) for zeolite RON = Roggianite Ca16[Be8Al16Si32O104(OH)16].19H2O starting with a T1 atom.at n=13A019217
- a(n) = [ Sum{(sqrt(j+1)-sqrt(i+1))^2} ], 1 <= i < j <= n.at n=48A025222
- Exactly half of first a(n) terms of A022300 are 1's (not known to be infinite).at n=26A025513
- a(n) = Sum_{k=0..n} (k+1) * A026747(n, n-k).at n=9A027228
- Number of partitions of n into parts not of form 4k+2, 16k, 16k+5 or 16k-5.at n=49A036022
- a(n) = (F(6*n+3) - 2)/32, where F = A000045 (the Fibonacci sequence).at n=4A049664
- McKay-Thompson series of class 10D for the Monster group.at n=9A058100
- Numbers which are the sum of their proper divisors containing the digit 0.at n=31A059461
- Start with a single triangle; at n-th generation add a triangle at each vertex, allowing triangles to overlap; sequence gives number of triangles in n-th generation.at n=20A061776
- a(n) = 6*n^2 + 12*n.at n=30A067726
- a(1) = 1; thereafter a(n) = 6*(2^(n-1) - 1).at n=10A068293
- Numbers k such that binomial(prime(k), k) is divisible by k^2.at n=16A081384
- Diagonal in array of n-gonal numbers A081422.at n=17A081437
- Number of pairs with two different elements which can be obtained by selecting unique elements from two sets with n+1 and n^2 elements respectively and n common elements.at n=18A085490
- Sum_{k=2..n} min(k,n-k)*phi(k)*(n-k).at n=21A092274
- Number of quasi-tetrominoes in an n X n bounding box.at n=7A094171
- Consider iteration of the function f(x) = sigma(phi(x)) = A062402(x). Sequence lists the numbers k such that the trajectory of k returns to k.at n=27A096998
- Numbers k such that 4*k-1, 8*k-1 and 16*k-1 are all primes.at n=38A101790
- Cascadence of (1+x)^3; a triangle, read by rows of 3n+1 terms, that retains its original form upon convolving each row with [1,3,3,1] and then letting excess terms spill over from each row into the initial positions of the next row such that only 3n+1 terms remain in row n for n>=0.at n=40A120919
- Main diagonal of triangle A120919 (cascadence of (1+x)^3); a(n) = A120919(n,n) for n>=0.at n=5A120922