6195
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
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 11520
- Proper Divisor Sum (Aliquot Sum)
- 5325
- 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
- 2784
- Möbius Function
- 1
- Radical
- 6195
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 186
- 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
- no
- Odd
- yes
Appears in sequences
- Lucky numbers with size of gaps equal to 16 (lower terms).at n=19A031898
- Lucky numbers with size of gaps equal to 18 (upper terms).at n=36A031901
- Expansion of (x^3+2*x+1) / ((x-1)^4*(x^2+x+1)^2).at n=41A038391
- Numerators of continued fraction convergents to sqrt(263).at n=7A041492
- Triangles in open triangular matchstick arrangement (triangle minus one side) of side n.at n=29A045947
- Squarefree odd numbers with exactly 4 distinct prime factors.at n=33A046390
- Partial sums of second pentagonal numbers with even index (A049453).at n=14A051895
- Numbers k such that 269*2^k + 1 is prime.at n=16A053351
- a(n) = binomial(n,4) + binomial(n,2).at n=20A055795
- Numbers k such that the Lucas Aurifeuillian primitive part B of Lucas(k) is prime.at n=47A061443
- Non-balanced numbers in A015765.at n=26A074868
- 2-apexes of omega: numbers k such that omega(k-2) < omega(k-1) < omega(k) > omega(k+1) > omega(k+2), where omega(m) = the number of distinct prime factors of m.at n=33A076762
- 2-nadirs of phi: numbers k such that phi(k-2) > phi(k-1) > phi(k) < phi(k+1) < phi(k+2).at n=29A076773
- Gregorian calendar years with Ascension Day in April.at n=19A084427
- Odd squarefree numbers k such that k/phi(k) > 2, where phi is Euler's totient function.at n=35A091495
- Matrix square of triangle A107876; equals matrix product of triangles: A107876^2 = A107862^-1*A107870 = A107867^-1*A107873.at n=39A107880
- Column 3 of triangle A107880.at n=5A107883
- Integers i such that 15*i = 27 X i.at n=45A115807
- Indices where 2 occurs in A124151.at n=22A124401
- Numbers k for which nontrivial positive magic squares of exactly 8 different orders with magic sum k exist. For a definition of nontrivial positive magic squares, see A125005.at n=22A125015