5249
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 5460
- Proper Divisor Sum (Aliquot Sum)
- 211
- 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
- 5040
- Möbius Function
- 1
- Radical
- 5249
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 129
- 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
- Let A(n) = #{(i,j): i^2 + j^2 <= n}, V(n) = Pi*n, P(n) = A(n) - V(n); A000099 gives values of n where |P(n)| sets a new record; sequence gives A(A000099(n)).at n=22A000323
- Number of partition graphs on n vertices.at n=9A007268
- a(n) = floor(log(5)^n).at n=18A014216
- Number of ordered triples of integers from [ 2,n ] with no global factor.at n=32A015633
- a(n) = least m such that if r and s in {1/1, 1/2, 1/3, ..., 1/n} satisfy r < s, then r < k/m < (k+4)/m < s for some integer k.at n=33A024846
- T(n,n-4), array T as in A038792.at n=19A038794
- a(n)=(s(n)+2)/9, where s(n)=n-th base 9 palindrome that starts with 7.at n=36A043078
- Numbers whose base-5 representation contains exactly two 1's and three 4's.at n=30A045258
- Number of ordered pairs of integers (x,y) with x^2+y^2 < n^2.at n=41A051132
- Numbers n such that sigma(n)^2 - phi(n)^2 is a perfect square.at n=22A057654
- Triangle T(n,k) giving number of nonisomorphic simple matroids of rank k on n labeled points (n >= 2, 2 <= k <= n).at n=37A058730
- Number of nonisomorphic simple matroids of rank 3 on n unlabeled points.at n=10A058731
- Composite n such that sigma(n)-phi(n) divides sigma(n)+phi(n).at n=42A061367
- Semiprimes p1*p2 such that p2>p1 and p2 mod p1 = 7.at n=24A064905
- Numbers n such that phi(phi(n)) = phi(sigma(n)) where phi is Euler's totient and sigma is the multiplicative sum-of-divisors function.at n=42A065555
- Smallest solution m to (n+1)*phi(m) = n*sigma(m), or -1 if no solution exists.at n=11A065824
- a(n) = A065824(A047845(n+1)).at n=3A065884
- Nonprime numbers n such that q=phi(n)/(sigma(n)-n-1) is an integer and n is not a prime square.at n=35A070161
- Octo numbers (a polygonal sequence): a(n) = 5*n^2 - 6*n + 2 = (n-1)^2 + (2*n-1)^2.at n=32A079273
- a(n) = (4*9^n + (-1)^n)/5.at n=4A083302