7009
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 7216
- Proper Divisor Sum (Aliquot Sum)
- 207
- 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
- 6804
- Möbius Function
- 1
- Radical
- 7009
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 181
- 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
- Expansion of cosh(tanh(x)*exp(x)).at n=8A009171
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 50 ones.at n=19A031818
- Numbers k such that k^12 == 1 (mod 13^3).at n=38A056086
- a(n) = min( x : x^3 + n^3 == 0 mod (x+n-1) ).at n=48A066486
- Least nontrivial multiple of the n-th prime beginning with 7.at n=37A078291
- Numbers m such that the numerator of Sum_{i=1..m} (i-1)/i is prime.at n=51A091815
- Semiprimes n such that 3*n - 2 is a square.at n=42A112393
- Semiprimes in A056109.at n=22A113528
- Products of two primes that are not Chen primes.at n=15A115719
- The number of compositions of n which cannot be viewed as stacks.at n=14A115981
- 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, 1), (-1, 1, -1), (0, 0, 1), (1, 0, 0)}.at n=8A149916
- Numbers expressible as a^2 + k b^2 with nonzero integers a,b, for k=2, k=3, k=5 and k=7.at n=31A155707
- Nimsum of pairs of consecutive Lucas numbers.at n=17A165794
- Triangle read by rows: T(n,k) is the number of weighted lattice paths in L_n having k (1,-1)-returns to the horizontal axis. The members of L_n are paths of weight n that start at (0,0), end on the horizontal axis and whose steps are of the following four kinds: an (1,0)-step with weight 1, an (1,0)-step with weight 2, a (1,1)-step with weight 2, and a (1,-1)-step with weight 1. The weight of a path is the sum of the weights of its steps.at n=31A182896
- Triangle, read by rows, such that row n equals the coefficients of x^(n^2+n-1+k) in F(x,n) for k = 1..n, where F(x,n) = (1 + x*F(x,n))*(1 + x^n/F(x,n)), for n>=1.at n=30A200171
- Column 3 of triangle A200171.at n=5A200172
- Triangle of coefficients of polynomials u(n,x) jointly generated with A209752; see the Formula section.at n=51A209751
- a(n) = 7*n^2 - 5*n + 1.at n=32A239449
- Partial sums of A072272.at n=52A253908
- Smallest m such that A259043(m) = n.at n=40A259046