7578
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 27
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 16458
- Proper Divisor Sum (Aliquot Sum)
- 8880
- 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
- 2520
- Möbius Function
- 0
- Radical
- 2526
- Omega Function (Ω)
- 4
- 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
- 39
- 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
- Number of ordered 5-tuples of integers from [ 1,n ] with no common factors among triples.at n=16A015656
- a(n) = (n+2)*a(n-1) + a(n-2), with a(0)=0, a(1)=1.at n=6A058308
- Triangle with a(n,n)=1, a(n,k)=(n-1)*a(n-1,k)+a(n-2,k) for n>k.at n=49A062323
- Dimension of the space of weight n cuspidal newforms for Gamma_1( 91 ).at n=24A063364
- Numbers k such that k^2 + prime(k) and k^2 - prime(k) are both primes.at n=39A064483
- Numbers n such that |real(zeta(1/2 + n*I))| exceeds all previous values, where zeta is the Riemann zeta function.at n=19A079630
- A Chebyshev transform of 3^n.at n=9A090413
- Triangle read by rows. Let S(k) be the sequence defined by F(0)=0, F(1)=1, F(n-1) + (n+k)*F(n) = F(n+1). E.g. S(0) = 0, 1, 1, 3, 10, 43, 225, 1393, 9976, 81201, ... Then S(0), S(1), S(2), ... are written vertically, next to each other, with the initial term of each on the next row down.at n=39A102472
- Triangle read by rows. Let S(k) be the sequence defined by F(0)=0, F(1)=1, F(n-1) + (n+k)*F(n) = F(n+1). E.g. S(0) = 0,1,1,3,10,43,225,1393,9976,81201, ... Then S(0), S(1), S(2), ... are written next to each other, vertically, with the initial term of each on the next row down. The order of the terms in the rows are then reversed.at n=41A102473
- Number of polyominoes consisting of 5 regular unit n-gons.at n=38A103471
- Expansion of f(q)*f(q^7)/(f(-q)*f(-q^7)) in powers of q where f() is a Ramanujan theta function.at n=32A123862
- a(n) = 1 if a(n-1) is prime, else a(n) = a(n-2)+a(n-3); starting with a(0) = 0, a(1) = a(2) = 1.at n=46A142884
- Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 0110-1111-0110 pattern in any orientation.at n=11A146924
- A recursion triangle sequence based on the Eulerian numbers: A(n,k)=n*A(n-1,k-1)+k*Eulerian(n-1,k).at n=24A157743
- A triangle related to the GF(z) formulas of the rows of the ED3 array A167572.at n=18A167583
- Number of weakly ordered plane trees with n leaves.at n=10A196545
- (A209982)/2.at n=39A209983
- Number of partitions of n such that the successive differences of consecutive parts are nondecreasing.at n=54A240026
- Number of partitions of n such that (number parts having multiplicity 1) is a part or (number of 1s) is a part.at n=33A241510
- T(n,k) = 2*(K(n,2)*I(k,2) - (-1)^(n+k)*I(n,2)*K(k,2)), where I(n,x) and K(n,x) are Bessel functions; triangle read by rows for 0 <= k <= n.at n=48A246654