7120
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 10
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 20
- Divisor Sum
- 16740
- Proper Divisor Sum (Aliquot Sum)
- 9620
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2816
- Möbius Function
- 0
- Radical
- 890
- Omega Function (Ω)
- 6
- Little Omega Function (ω)
- 3
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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 75
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = solution to the postage stamp problem with 3 denominations and n stamps.at n=47A001208
- Number of down-up permutations of n+4 starting with n+1.at n=6A006213
- Boustrophedon version of triangle of Euler-Bernoulli or Entringer numbers read by rows.at n=51A008280
- Triangle of Euler-Bernoulli or Entringer numbers read by rows.at n=51A008281
- Triangle of Euler-Bernoulli or Entringer numbers read by rows: T(n,k) is the number of down-up permutations of n+1 starting with k+1.at n=41A008282
- Read across rows of Euler-Bernoulli or Entringer triangle.at n=26A008283
- Triangle of Euler-Bernoulli or Entringer numbers.at n=39A010094
- a(n) = floor( n*(n-1)*(n-2)/26 ).at n=58A011908
- Number of noninvertible 2 X 2 matrices over Z/nZ (determinant is a divisor of 0).at n=8A020479
- dot_product(n,n-1,...2,1)*(7,8,...,n,1,2,3,4,5,6).at n=23A026066
- a(n) is the n-th diagonal sum of left justified array T given by A027960.at n=27A027975
- Number of rooted trees with n nodes with every leaf at height 4.at n=19A048809
- The array in A059502 read by antidiagonals in 'up' direction.at n=53A059503
- Transform of A059502 applied to sequence 2,3,4,...at n=8A059505
- Numbers k such that phi(x) = k has exactly 11 solutions.at n=22A060674
- Triangle in which rows are permutations of the rows of A008282.at n=42A064192
- Number of subgroups of the group C_n X C_n X C_n (where C_n is the cyclic group of order n).at n=17A064803
- a(n) = n*(14*n^2 - 21*n + 13)/6.at n=15A071229
- Concatenation of n-th prime and n in decimal notation.at n=19A075110
- Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=1, r=5, I={0,1,3}.at n=42A079957