6609
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
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 8816
- Proper Divisor Sum (Aliquot Sum)
- 2207
- 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
- 4404
- Möbius Function
- 1
- Radical
- 6609
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 137
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- a(n) = position of 3*n^2 in sequence A025051 (numbers of form j*k + k*i + i*j, without repetitions, where 1 <= i <= j <= k).at n=46A025056
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 54.at n=21A031552
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 42 ones.at n=29A031810
- Left-hand border of triangle A046937.at n=8A038561
- Numbers k such that k^4 can be written as a sum of four positive 4th powers with no common factor.at n=17A039664
- Triangle read by rows. Same rule as Aitken triangle (A011971) except T(0,0) = 1, T(1,0) = 2.at n=35A046937
- Triangle read by rows. Same rule as Aitken triangle (A011971) except T(0,0) = 1, T(1,0) = 2.at n=36A046937
- Sequence formed from rows of triangle A046937.at n=29A046938
- Values of n such that 90n+11, 90n+13, 90n+17, 90n+19 are all primes.at n=40A051897
- Smallest integer >= 0 of the form x^4 - n^3.at n=27A070928
- Numbers m such that (15m-4, 15m-2, 15m+2, 15m+4) is a prime quadruple.at n=36A112540
- a(n) = 8*n^2 - 4*n - 3.at n=28A118057
- Number of essentially different semi-magic squares of order 3 with semimagic sum n.at n=23A122751
- Numbers ending in 1, 3, 7 or 9 such that either prepending or following them by one digit doesn't produce a prime.at n=35A124666
- 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, 0), (-1, 0, 1), (-1, 1, -1), (0, -1, 1), (1, 1, 0)}.at n=8A149186
- Partial sums of A138202.at n=16A164940
- a(n) = 6n + 3^n.at n=7A173391
- Array of coefficients of powers of x^2 for S(2*n,x)^3 with Chebyshev's S polynomials A049310.at n=38A220666
- 5*n^2 + 4*n - 15.at n=35A239794
- a(n) is the index of the first occurrence of n in A166006.at n=10A278737