7241
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 7812
- Proper Divisor Sum (Aliquot Sum)
- 571
- 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
- 6672
- Möbius Function
- 1
- Radical
- 7241
- 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
- yes
- 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
- Number of asymmetric trees with n nodes (also called identity trees).at n=18A000220
- Numbers k such that the continued fraction for sqrt(k) has period 35.at n=15A020374
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted then there are a pair of central terms both equal to 5.at n=36A031418
- Numbers having four 1's in base 8.at n=27A043428
- Dimension of the space of weight n cuspidal newforms for Gamma_1( 79 ).at n=28A063352
- Semiprimes p1*p2 such that p2 > p1 and p2 mod p1 = 11.at n=25A064909
- Numbers n such that sopf(phi(n)) = phi(sopf(n)), where sopf(x) = sum of the distinct prime factors of x.at n=25A076531
- a(n)=(-1)^n(1 - (1/12)n(n + 1)(12 - n + n^2)).at n=17A080275
- a(n) = floor(e*(n+3)!) - (n+3)*(n+2)*(n+1)*n*floor(e*(n-1)!).at n=16A080770
- Sum of the first n primes whose indices are primes.at n=28A083186
- Number of subsets A of {1..n} such that there are no solutions to a+b+c=d for a,b,c,d in A.at n=17A093970
- Start with 1015 and repeatedly reverse the digits and add 4 to get the next term.at n=58A117807
- a(1)=a(2)=1. a(n+1) = a(n) + a(smallest prime dividing n).at n=38A128216
- Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a zee 1,1 1,2 2,2 2,3 in any orientation.at n=12A145956
- Number of lines through at least 2 points of a 5 X n grid of points.at n=36A160845
- a(n) = 6*a(n-1) - 7*a(n-2) for n > 1; a(0) = 3, a(1) = 17.at n=5A164305
- G.f. A(x) satisfies A(x) = 1/(1 - x*A(2*x)^4).at n=4A171194
- A185128(n) is the a(n)-th triangular number.at n=41A185223
- a(n) = n^3 - 2*n^2 + 2*n + 1.at n=19A188947
- Numbers k such that tau(k-1) = (tau(k))^2 = tau(k+1), where tau(k) = A000005(k) (number of divisors of k).at n=26A190266