6490
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 12960
- Proper Divisor Sum (Aliquot Sum)
- 6470
- 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
- 2320
- Möbius Function
- 1
- Radical
- 6490
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 137
- 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
- a(n) = 1 + Sum_{i=1..n} (n-i+1)*phi(i).at n=39A005598
- Sums of five consecutive squares: a(n) = n^2 + (n+1)^2 + (n+2)^2 + (n+3)^2 + (n+4)^2.at n=34A027578
- Numbers whose base-4 representation contains exactly four 1's and three 2's.at n=10A045108
- Analog of A059226 in which left diagonal is all 1's.at n=26A059274
- Squarefree numbers having exactly three prime gaps.at n=31A073489
- Numbers having exactly three prime gaps in their factorization.at n=37A073495
- Non-balanced numbers in A015765.at n=29A074868
- How many more primes than irreducible GF(2)[X] polynomials there are in range [0,2^n].at n=18A091231
- G.f.: Sum((1-x)^(2*l)*Sum(x^((2*l-1)*k)/(1-2*x+x^k)^(2*l),k=1..infinity),l=1..infinity).at n=13A105205
- Numbers n such that A001414(n) is a golden semiprime, where A001414 is the sum of primes dividing n (with repetition).at n=44A108219
- a(n) = number of conjugacy classes in PSL_3(prime(n)).at n=33A124679
- a(n) = (7*n^2 + 15*n + 2) / 2.at n=42A131874
- Numbers such that the digital sums in bases 3, 4, 5 and 6 all are equal.at n=14A135126
- Values of x in solutions (x,y,z) to the Diophantine equation x^3-x^2+y^3-y^2=z^3-z^2, with 1<x<y<z.at n=20A138667
- 11 times pentagonal numbers: 11*n*(3n-1)/2.at n=20A153449
- a(n) = 250*n - 10.at n=25A154378
- Number of ways to place 2 nonattacking bishops on an n X n board.at n=10A172123
- Ceiling(n/3)-perfect numbers.at n=13A177084
- Numbers n such that 2n/sigma(n) - 1 = 1/x for some integer x.at n=43A222264
- Numbers whose deficiency is 20: sigma(k) - 2*k = -20.at n=4A223607