7989
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 33
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 10656
- Proper Divisor Sum (Aliquot Sum)
- 2667
- 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
- 5324
- Möbius Function
- 1
- Radical
- 7989
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 52
- 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
- no
- Odd
- yes
Appears in sequences
- Let S denote the palindromes in the language {0,1,2}*; a(n) = number of words of length n in the language SS.at n=11A007056
- Numbers k such that 3^k - 2 is prime.at n=23A014224
- a(n) = Sum_{i=0..n} Sum_{j=0..i} T(i,j), T given by A026519.at n=10A026533
- Numbers k that divide the (right) concatenation of all numbers <= k written in base 13 (most significant digit on left).at n=34A029458
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 58.at n=39A031556
- a(n) = a(1) + a(2) + ... + a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1 and a(2) = a(3) = 2.at n=13A049952
- a(n) = floor(n^m) where m = Sum_{k=1..n} (1/k).at n=14A067038
- a(n) = Sum_{k=0..floor(n/5)} C(n-3*k,2*k) * 2^k.at n=20A098577
- Number of compositions of n in which the least part is odd.at n=13A103419
- Concatenations of pairs of primes that differ by 10.at n=9A104719
- a(n) = 6 + floor((1 + Sum_{j=1..n-1} a(j))/3).at n=25A120152
- a(n) = least k such that the remainder when 20^k is divided by k is n.at n=10A128160
- Numbers of the form 68+p^2 (where p is a prime).at n=23A138691
- Total number of configurations that appear in the cycles, in the glass worms (or vers de verres) game with n glasses.at n=10A176336
- Numbers with rounded up arithmetic mean of digits = 9.at n=16A178369
- Degree of denominator of GF for number of ways to place k nonattacking queens on an n X n board.at n=10A178717
- Triangle of coefficients of polynomials u(n,x) jointly generated with A210599; see the Formula section.at n=41A210598
- Number of nX4 arrays of occupancy after each element moves to some horizontal or antidiagonal neighbor, without move-in move-out straight through or left turns.at n=5A221751
- T(n,k)=Number of nXk arrays of occupancy after each element moves to some horizontal or antidiagonal neighbor, without move-in move-out straight through or left turns.at n=41A221755
- Number of 6Xn arrays of occupancy after each element moves to some horizontal or antidiagonal neighbor, without move-in move-out straight through or left turns.at n=3A221760