7864
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 25
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 14760
- Proper Divisor Sum (Aliquot Sum)
- 6896
- 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
- 3928
- Möbius Function
- 0
- Radical
- 1966
- Omega Function (Ω)
- 4
- 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
- 145
- 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 elements w of the Weyl group D(n) such that the roots sent negative by w span an Abelian subalgebra of the Lie algebra.at n=7A007851
- Number of distinct products i*j with 0 <= i, j <= n-th prime.at n=38A027419
- Sequence satisfies T(a)=a, where T is defined below.at n=52A027592
- Expansion of (theta_3(z)*theta_3(23z)+theta_2(z)*theta_2(23z))^4.at n=25A028660
- Numbers k such that us(k) = primepi(k), where us(k) is the sum of the aliquot unitary divisors of k (A034460), and primepi(k) is the number of primes <= k (A000720).at n=9A037176
- Row sums of triangle A049324.at n=9A049348
- Number of compositions (ordered partitions) of n that are concave-down sequences.at n=49A070211
- Highest m such that prime(m) divides the n-th pandigital (A050278).at n=9A071924
- G.f. A(x) satisfies: A(x)^4 = A(x^2)^2 + 4*x.at n=11A107086
- Expansion of 1/sqrt(1-4x-8x^2-24x^3+36x^4).at n=6A108490
- One third of the sum of the first n primes, when an integer.at n=30A112270
- Triangle read by rows: numbers of isomers of unbranched a-4-catapolyoctagons.at n=50A120649
- The first 8 values are predefined, the remaining set to a(n) = 48*prime(n)+n+2.at n=37A129025
- Triangle, read by rows, where T(n,k) = T(n,k-1) + n*T(n-1,k-1) for n>0 and k>0, with T(n,0) = T(n-1,n-1) for n>0 and T(0,0) = 1.at n=22A132007
- Number of binary words of length n containing at least one subword 10001 and no subwords 10^{i}1 with i<3.at n=28A143283
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 0, 1), (0, 1, 0), (1, 0, 1), (1, 1, -1)}.at n=7A150294
- Number of line segments connecting exactly 5 points in an n x n grid of points.at n=24A177721
- Numbers n such that gcd(n, phi(n)) = gcd(phi(n), sigma(n)) = gcd(sigma(n), n) = tau(n).at n=17A217301
- Numbers n such that 2*n + {3, 5, 9, 11} are all primes.at n=14A222960
- a(n) = n*prime(prime(n)) - prime(n)^2.at n=34A230098