7623
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 18
- Divisor Sum
- 13832
- Proper Divisor Sum (Aliquot Sum)
- 6209
- 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
- 3960
- Möbius Function
- 0
- Radical
- 231
- Omega Function (Ω)
- 5
- 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
- 70
- 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
- no
- Odd
- yes
Appears in sequences
- Expansion of x^3*(5-2*x)*(1-x^3)/(1-x)^4.at n=40A000338
- a(n) is nonsquarefree and is sum of first k nonsquarefrees for some k.at n=32A013935
- a(n) = 7*n^2.at n=33A033582
- Odd numbers with exactly 5 palindromic prime factors (counted with multiplicity).at n=29A046375
- Partial sums of A051798.at n=8A051879
- n is odd and sum of digits of n equals the numbers of divisors of n.at n=36A057532
- Sum of divisors of twice square numbers.at n=35A065765
- Numbers that when multiplied by the product of their nonzero digits produce a square.at n=52A066565
- Number of ways to build a contiguous building with n LEGO blocks of size 1 X 2 on top of a fixed block of the same size so that the building is flat, i.e., with all blocks in parallel position and symmetric after a rotation by 180 degrees.at n=13A123769
- Triangle read by rows: T(n,k) is the number of set partitions of {1,2,...,n} (or of any n-set) having k blocks of even size (0<=k<=floor(n/2)).at n=27A124322
- a(n) = Sum_{k=0..n} 2^k*A124526(n,k) for n>=0.at n=8A124528
- Numbers k for which nontrivial positive magic squares of exactly 9 different orders with magic sum k exist. For a definition of nontrivial positive magic squares, see A125005.at n=5A125016
- Special values of hypergeometric function of type 2F2: a(n)=3^n*(n!)^2* 2F2(n+1, n+1; 1, 1; 3)*exp(-3),n=0,1...at n=2A127455
- Partial sums of A130237.at n=43A130238
- Column l=3 of irregular triangle in A133709.at n=9A133710
- a(n) = 3*a(n-1) - 4*a(n-3), with a(0)=1, a(1)=2, a(2)=4, a(3)=9.at n=12A136298
- a(n) = ((2^b-1)/phi(n))*Sum_{d|n} Moebius(n/d)*d^(b-1) for b = 6.at n=2A160896
- a(n) = n-th odd nonprime * n-th odd number.at n=31A163506
- a(n) = 63*((10^n - 1)/9)^2.at n=1A178634
- Irregular triangle: the coefficient [x^k] of the polynomial (1-x)^(2*n-1) * Sum_{s>=0} A001263(n+2*s,2*s+1)*x^s in row n >= 1 and column k >= 0.at n=24A178657