7320
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 32
- Divisor Sum
- 22320
- Proper Divisor Sum (Aliquot Sum)
- 15000
- 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
- 1920
- Möbius Function
- 0
- Radical
- 1830
- Omega Function (Ω)
- 6
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 132
- 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(2n) = a(2n-1) + 2a(2n-2), a(2n+1) = a(2n) + a(2n-1), with a(1) = 2 and a(2) = 3.at n=14A001882
- a(n) = floor(n(n+2)(2n+1)/8).at n=30A002717
- Theta series of A_5 lattice.at n=37A008445
- a(n) = floor(n*(n - 1)*(n - 2)/31).at n=62A011913
- Fibonacci sequence beginning 0, 12.at n=15A022346
- a(n) = 4*n*(2*n + 1).at n=30A033586
- Bisection of A028289.at n=44A038390
- Denominators of continued fraction convergents to sqrt(646).at n=7A042241
- Star of David matchstick numbers: a(n) = 6*n*(3*n+1).at n=20A045946
- a(n) in base 11 is a repdigit.at n=35A048335
- First element r of (-1)sigma sociable triple (r,s,t): s=(-1)sigma(r), t=(-1)sigma(s), r=(-1)sigma(t), where if x=Product p(i)^r(i), then (-1)sigma(x)=Product(-1+(Sum p(i)^s(i), s(i)=1 to r(i))).at n=16A049057
- E.g.f. 1/(1-4x-x^2).at n=4A052630
- Expansion of e.g.f.: exp(x^2/(1 - x)^2).at n=6A052887
- Numbers k such that k | sigma_5(k).at n=40A055709
- Composite numbers k such that phi(k) divides sigma(k) - 2*k.at n=16A068412
- Products of members of pairs in A075333.at n=20A075337
- Smallest number having exactly n divisors that are not greater than the number's greatest prime factor.at n=15A087134
- Numbers that can be expressed as the difference of the squares of primes in just three distinct ways.at n=25A090782
- Triangle, read by rows, where the n-th row lists the coefficients of the polynomial of degree n, with root -1, that generates the n-th diagonal of this sequence.at n=48A091173
- Triangle, read by rows, where e.g.f. A(x,y) satisfies: A(x,y) = exp(x*y*A(x,y+1)) and A(x,y) = Sum_{n>=0} Sum_{k>=0} T(n,k)/n!*x^n*y^k.at n=19A096542