7848
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
- 4
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 21450
- Proper Divisor Sum (Aliquot Sum)
- 13602
- 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
- 2592
- Möbius Function
- 0
- Radical
- 654
- Omega Function (Ω)
- 6
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 26
- 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 connected regular graphs of degree 5 (or quintic graphs) with 2n nodes.at n=6A006821
- a(n) = Sum_{k=0..2n-3} T(n,k) * T(n,k+3), with T given by A027023.at n=3A027049
- Four times second pentagonal numbers: a(n) = 2*n*(3*n+1).at n=36A033580
- a(1) = 1; for n >= 2, a(n) = n times the reverse of a(n-1).at n=7A034874
- Numbers having four 0's in base 6.at n=16A043372
- a(n) = Sum_{m=1..n, k=1..m} T(m,k), array T as in A049834.at n=39A049836
- From solution to a counting problem.at n=8A059775
- Triangular array C(n, r) = number of connected r-regular graphs with n nodes, 0 <= r < n.at n=71A068934
- Smallest even number divisible by 2n which is nontotient, i.e., in A005277.at n=35A071616
- Triangle formed from coefficients of the polynomials p(1)=x, p(n+1) = (n + x*(n+1))*p(n) + x*x*(d/dx)p(n).at n=22A075856
- Number of 4 X n (0,1) matrices such that each row and each column is nondecreasing or nonincreasing.at n=8A086114
- Least k such that k*(Mersenne_prime(n)^2) + 1 is prime.at n=23A098819
- Structured disdyakis triacontahedral numbers (vertex structure 11).at n=7A100158
- Sum of ordered 3 prime sided prime triangles.at n=35A105100
- a(n) = a(n-1) + 2*a(n-2) - 2*a(n-3) + a(n-5).at n=19A116157
- Terms of A068563 that are not terms of A124240.at n=32A124241
- a(n) = 9*a(n-1) + 9*a(n-2), n>2; a(0)=1, a(1)=8, a(2)=80.at n=4A155144
- a(n) = n*(n+1)*(7*n^2 - n - 4)/4.at n=8A172077
- Sequence A154692 adjusted to leading one:t(n,m)=A154692(n,m)-A154692(n,0)+1.at n=24A174667
- Number of permutations of 1..n with sum (i-p(i))^2 <= n*(n-1)/2.at n=8A179263