7126
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
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 12240
- Proper Divisor Sum (Aliquot Sum)
- 5114
- 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
- 3048
- Möbius Function
- -1
- Radical
- 7126
- Omega Function (Ω)
- 3
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 163
- 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
- yes
- Odd
- no
Appears in sequences
- McKay-Thompson series of class 5B for the Monster group with a(0) = 0.at n=30A007252
- a(n) = Sum_{k=0..n-3} T(n,k) * T(n,k+3), with T given by A026725.at n=5A027210
- Numbers whose set of base-13 digits is {2,3}.at n=26A032813
- Every run of digits of n in base 13 has length 2.at n=38A033011
- McKay-Thompson series of class 5B for the Monster group with a(0) = 1.at n=30A045483
- Numbers k such that k! is divisible by the square of (f+d)!^2 for d = 0, 1 and 2 (and possibly larger d), where f = floor(k/2).at n=40A056068
- McKay-Thompson series of class 5B for the Monster group with a(0) = -6.at n=30A106248
- a(n) = Sum_{k + l*m <= n} (k + l*m), with 0 <= k,l,m <= n.at n=15A106846
- A Langford-like sequence.at n=37A108401
- Shadow of N (natural numbers), also of Champernowne's shadow.at n=43A110623
- Collatz (or 3x+1) trajectory starting at 703.at n=7A161021
- a(n) = n*n in the arithmetic where when digits are to be added they are multiplied, and when they are to be multiplied they are added.at n=38A169921
- Number of (n+1) X 4 binary arrays with every 2 X 2 subblock commuting with each of its horizontal and vertical 2 X 2 subblock neighbors.at n=12A186456
- Total number of positive integers below 10^n requiring 12 positive biquadrates in their representation as sum of biquadrates.at n=4A186669
- E.g.f. A(x) satisfies: A(x) = x*(2*exp(A(x)) - exp(2*A(x))).at n=6A200904
- Number of (w,x,y,z) with all terms in {1,...,n} and |w-x|=w+|y-z|.at n=28A212685
- Number of rooted trees with n nodes such that no more than two subtrees corresponding to children of any node have the same number of nodes.at n=13A213920
- Sum of the squared parts of the partitions of n into exactly two parts.at n=27A226141
- Number of isoscent sequences of length n with maximal number of descents.at n=26A243484
- Numbers n such that the smallest prime divisor of n^2+1 is 61.at n=38A248549