7524
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
- 2
Divisibility
- Divisor Count
- 36
- Divisor Sum
- 21840
- Proper Divisor Sum (Aliquot Sum)
- 14316
- 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
- 2160
- Möbius Function
- 0
- Radical
- 1254
- 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
- yes
- Harshad Number
- yes
- 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
- Position of n^3 + 9 in A024975.at n=40A024979
- Average theta series of odd unimodular lattices of dimension 11 (multiplied by 31).at n=2A029813
- Every run of digits of n in base 5 has length 2.at n=39A033003
- Number of 5-ary rooted trees with n nodes and height exactly 7.at n=14A036638
- Numbers n such that n | Sigma_2(n) + Sigma_1(n) + Sigma_0(n).at n=12A057852
- Dimension of the space of weight n cuspidal newforms for Gamma_1( 99 ).at n=27A063372
- Numbers k such that prime(k+3)-(k+3)*tau(k+3) = prime(k-3)-(k-3)*tau(k-3) where tau(k) = A000005(k) is the number of divisors of k.at n=20A067355
- The number of rectangles (orthogonal or not) with corners on an n X n grid of points.at n=11A085582
- a(1) = 1, a(n) = smallest multiple of n such that the concatenation (n>1) a(n)a(n-1)... a(2) a(1) is a prime.at n=43A089330
- Numbers k such that 10^k + 5*R_k + 4 is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=17A102938
- Triangle read by rows: T(n,k) is the number of deco polyominoes of height n and having k columns ending at an even level (1<=k<=n). A deco polyomino is a directed column-convex polyomino in which the height, measured along the diagonal, is attained only in the last column.at n=43A121698
- Triangle read by rows: T(n,k) is the number of Dyck paths of semilength n having k long ascents and long descents. A long ascent (descent) in a Dyck path is a maximal sequence of at least 2 consecutive up (down) steps.at n=65A127155
- Nonnegative values x of solutions (x, y) to the Diophantine equation x^2+(x+833)^2 = y^2.at n=23A129010
- a(n) = n^5 - n^3 - n^2.at n=6A133070
- Triangle, read by rows, equal to R^2, the matrix square of R = A135894.at n=41A135895
- 3 times 11-gonal (or hendecagonal) numbers: a(n) = 3*n*(9*n-7)/2.at n=24A153783
- Number of binary strings of length n with no substrings equal to 0000 0110 or 0111.at n=16A164438
- a(n) = (6 + 10*n + 5*n^2 + n^3)/2.at n=23A164845
- Multiples of 19 whose digit reversal - 1 is also a multiple of 19.at n=17A166399
- Totally multiplicative sequence with a(p) = 7p-2 for prime p.at n=29A166671