7522
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 11286
- Proper Divisor Sum (Aliquot Sum)
- 3764
- 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
- 3760
- Möbius Function
- 1
- Radical
- 7522
- 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
- 39
- 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
- yes
- Odd
- no
Appears in sequences
- Numbers k such that the continued fraction for sqrt(k) has period 17.at n=40A020356
- 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=38A031418
- Let (u1,u2) be successive untouchable numbers such that phi(u1) = phi(u2); sequence gives values of u1.at n=22A048189
- If n = 0 or 1 then a(n) = 1; if n = 2, 3 or 4 then a(n) = 0; otherwise a(n) = (n+1)*a(n-1)-(n-2)*a(n-2)-(n-5)*a(n-3)+(n-3)*a(n-4).at n=9A085372
- Expansion of psi(x^3)^2 / f(-x^2) in powers of x where psi(), f() are Ramanujan theta functions.at n=54A097196
- Number of partitions of n with odd crank.at n=35A124228
- a(n) = 2*a(n-1) + prime(n) - prime(n-1), a(1)=2, where prime(n) denotes the n-th prime.at n=11A125180
- Set m = 0, n = 1. Find smallest k >= 2 such that pi(k) = (k-pi(k)) - (m-pi(m)); set a(n) = pi(k), m = k, n = n+1. Repeat.at n=43A131872
- Row sums of triangle A134637.at n=9A134638
- Partial sums of A072857.at n=12A173052
- Dispersion of (floor(8*n/3)), by antidiagonals.at n=46A191543
- Beach-Williams Pell numbers of type 2p (p prime).at n=5A212074
- Number of nondecreasing -n..n vectors of length 3 whose dot product with some nondecreasing -n..n vector equals 3.at n=17A226411
- Triangle read by rows: T(n,k) gives the number of ballot sequences of length n having k largest parts, n >= k >= 0.at n=56A238123
- Number of ballot sequences of length n having exactly 1 largest part.at n=10A238124
- Number of length 3 0..n arrays with each partial sum starting from the beginning no more than two standard deviations from its mean.at n=18A244834
- Expansion of f(x^3, x^9) * f(x^6, x^6) / f(-x, -x^2) in powers of x where f(,) is Ramanujan's general theta function.at n=27A257655
- a(n) is the n-th b > 1 such that p = prime(n) satisfies b^(p-1) == 1 (mod p^2).at n=44A280721
- Smallest k such that A285481(k) >= n, i.e., lowest d where the smallest integer radius needed for a d-dimensional ball to have a volume >= 1 is at least n.at n=21A285482
- Number of nX3 0..1 arrays with every element equal to 1, 2, 3, 5 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=5A301349