7095
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
- 16
- Divisor Sum
- 12672
- Proper Divisor Sum (Aliquot Sum)
- 5577
- 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
- 3360
- Möbius Function
- 1
- Radical
- 7095
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 57
- 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
- a(n) = floor(n*(n-1)*(n-2)/12).at n=45A011894
- Orders of cyclotomic polynomials containing a coefficient the absolute value of which is >= 5.at n=31A013593
- Number of balls in pyramid with base either a regular hexagon or a hexagon with alternate sides differing by 1 (balls in hexagonal pyramid of height n taken from hexagonal close-packing).at n=30A019298
- a(n) = n*(13*n + 1)/2.at n=33A022271
- Expansion of (x^3+2*x+1) / ((x-1)^4*(x^2+x+1)^2).at n=43A038391
- Denominators of continued fraction convergents to sqrt(417).at n=9A041793
- At stage 1, start with a unit square. At each successive stage add 4*(n-1) new squares around outside with edge-to-edge contacts. Sequence gives number of squares (regardless of size) at n-th stage.at n=21A056640
- Let p(k) denote k-th prime; consider solutions (n,m) of the Diophantine system {p(p(n)+1)-p(p(n))=2, p(p(n))-6.p(p(m))=-1} (*); sequence gives values of m.at n=25A065511
- a(0)=1, a(n) is the smallest integer > a(n-1) such that the largest element in the simple continued fraction for S(n)= 1/a(0)+1/a(1)+1/a(2)+...+1/a(n) equals 2n.at n=43A070898
- 2-nadirs of phi: numbers k such that phi(k-2) > phi(k-1) > phi(k) < phi(k+1) < phi(k+2).at n=35A076773
- Triangle of 3-Narayana numbers, N(n,k), for n >= 1, 0 <= k <= 2n-2.at n=28A087647
- Triangle of 3-Narayana numbers, N(n,k), for n >= 1, 0 <= k <= 2n-2.at n=32A087647
- Odd squarefree numbers k such that k/phi(k) > 2, where phi is Euler's totient function.at n=40A091495
- Array read by antidiagonals: T(r,n) = number of two-stack sortable r-permutations.at n=32A093346
- Expansion of (1-x)/((1-2*x)*(1-2*x-x^2)).at n=9A106514
- a(n) = A001333(n) - (-2)^(n-1), n > 0.at n=10A111108
- Number of squares in the interior of the square with vertices (n,0), (0,n), (-n,0) and (0,-n) in a square (x,y)-grid.at n=21A111746
- Numerator of (n-1)*n*(n+1)/12.at n=43A138190
- Starts with 2; has two properties: concatenation of its digits is same string as concatenation of digits of its first differences and sequence and first differences have no term in common. When there is a choice in choosing the next term in the first differences, choose the smallest number not yet present in either the sequence or its first differences.at n=34A139334
- Number of reduced words of length n in Coxeter group on 3 generators S_i with relations (S_i)^2 = (S_i S_j)^5 = I.at n=13A163314