7147
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
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 8176
- Proper Divisor Sum (Aliquot Sum)
- 1029
- 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
- 6120
- Möbius Function
- 1
- Radical
- 7147
- 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
- 101
- 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(1) = 3; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.at n=40A033681
- Numbers whose base-4 representation contains exactly three 2's and three 3's.at n=27A045151
- a(n) = floor(n^n / n!).at n=11A055775
- Smallest number of triangulations of n points in the plane.at n=10A063544
- Numbers k such that d(k) + d(k+1) + d(k+2) = 8, where d(k) = A001223.at n=31A064026
- Expansion of (1+x^4*C)*C^4, where C = (1-(1-4*x)^(1/2))/(2*x) is g.f. for Catalan numbers, A000108.at n=7A071745
- a(1)=1; a(n) = a(n-1) + [sum of all decimal digits present so far in the sequence].at n=36A072921
- Beginning with 1, minimum value such that gcd(a(2n-1),a(2n)) = 1, gcd(a(2n),a(2n+1))>1 and a(n) > a(n-1).at n=45A091856
- a(1) = 668; for n > 1, a(n) = a(n-1) + 1 + sum of distinct prime factors of a(n-1) that are < a(n-1).at n=27A105212
- a(n) = floor(n^(n/2)/n!!).at n=21A114854
- a(n) = floor(n^(n/3)/n!!!).at n=32A114863
- s(n) = floor(n^(n/5)/n!!!!!).at n=54A114869
- Triangle read by rows: T(n,k) is the number of deco polyominoes of height n having k cells in the second column (n>=1, k>=0). A deco polyomino is a directed column-convex polyomino in which the height, measured along the diagonal, is attained only in the last column.at n=31A121581
- a(1) = 3, a(n + 1) = 1 + a(n) + least odd prime factor of a(n).at n=25A144751
- 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), (0, 1, -1), (0, 1, 1), (1, 0, 0)}.at n=8A149945
- Positive numbers y such that y^2 is of the form x^2+(x+833)^2 with integer x.at n=27A156835
- T(n,k)=Number of (n+1)X(k+1) 0..5 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors.at n=6A186486
- T(n,k)=Number of (n+1)X(k+1) 0..5 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors.at n=9A186486
- T(n,m)=Number of (n+1)X2 0..m arrays with every 2X2 subblock commuting with each of its vertical 2X2 subblock neighbors.at n=31A187363
- T(n,m)=Number of (n+1)X5 0..m arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors.at n=10A189174