8409
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
- 11216
- Proper Divisor Sum (Aliquot Sum)
- 2807
- 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
- 5604
- Möbius Function
- 1
- Radical
- 8409
- 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
- 65
- 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
- Coefficient of q^(2n-1) in the series expansion of Ramanujan's mock theta function f(q).at n=43A000199
- 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 60.at n=36A031558
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 46 ones.at n=28A031814
- Numbers n such that n = pi(n)*k + 1 for some k.at n=22A065136
- Number of partitions of n in which the number of parts divides n.at n=43A067538
- a(n) is the smallest integer k > 1 such that k > n * pi(k), where pi() denotes the prime counting function.at n=7A086511
- Beginning with 1, numbers such that the differences a(k)-a(k-1) are distinct and every concatenation n>1 is prime.at n=45A090504
- Indices of primes in sequence defined by A(0) = 43, A(n) = 10*A(n-1) - 27 for n > 0.at n=14A101713
- Binomial transform of the "1,2,3,..." triangle.at n=47A125027
- 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), (0, 1, 0), (1, 0, 0), (1, 1, -1)}.at n=8A149924
- Number of ways to place zero or more nonadjacent 0,0 1,0 2,0 3,1 3,2 4,1 5,2 6,3 polyhexes in any orientation on a planar nXnXn triangular grid.at n=7A155395
- a(n) = 841*n - 1.at n=9A158402
- a(n) = 10*n^2 - 1.at n=28A158447
- Number of binary strings of length n with no substrings equal to 0001 0010 or 0100.at n=12A164445
- Monotonic ordering of set S generated by these rules: if x and y are in S then (x+1)(y+1) is in S, and 2 is in S.at n=27A192518
- Row sums of triangular matrix defined by exp(L) where L(n,k) = C(2*n, 2*k+1) for n>=0, k=0..n.at n=5A246387
- T(n,k)=Number of (n+1)X(k+1) arrays of permutations of 0..(n+1)*(k+1)-1 with each element having directed index change 1,0 1,1 0,-1 or -1,1.at n=47A264569
- Number of (3+1)X(n+1) arrays of permutations of 0..n*4+3 with each element having directed index change 1,0 1,1 0,-1 or -1,1.at n=7A264571
- Numbers n such that 10^n-9^(n-1) is prime.at n=13A272621
- Let p = n-th prime == 3 mod 8; a(n) = sum of quadratic nonresidues mod p that are < p/2.at n=19A282724