2839
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 3024
- Proper Divisor Sum (Aliquot Sum)
- 185
- 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
- 2656
- Möbius Function
- 1
- Radical
- 2839
- 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
- 128
- Smith Number
- yes
- 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
- Heptagonal numbers (or 7-gonal numbers): n*(5*n-3)/2.at n=34A000566
- Centered triangular numbers: a(n) = 3*n*(n-1)/2 + 1.at n=43A005448
- Number of stable forests with n nodes.at n=13A006544
- Coordination sequence T1 for Zeolite Code VFI.at n=41A008245
- Coordination sequence T2 for Zeolite Code iRON.at n=37A009882
- Coordination sequence T2 for Zeolite Code RTH.at n=37A009894
- Odd heptagonal numbers (A000566).at n=17A014637
- Numbers k such that the continued fraction for sqrt(k) has period 52.at n=9A020391
- a(n) = least m such that if r and s in {1/1, 1/3, 1/5, ..., 1/(2n-1)} satisfy r < s, then r < k/m < (k+2)/m < s for some integer k.at n=23A024841
- In base 11, a(n) = sum of digits of Lucas(a(n)).at n=32A025491
- a(n) = A026626(2*n, n-2).at n=5A026629
- 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 53.at n=2A031551
- Base-5 palindromes that start with 4.at n=25A043009
- Numbers n such that string 0,4 occurs in the base 9 representation of n but not of n-1.at n=37A044255
- Numbers n such that string 3,9 occurs in the base 10 representation of n but not of n-1.at n=31A044371
- Numbers n such that string 0,4 occurs in the base 9 representation of n but not of n+1.at n=37A044636
- Numbers n such that string 3,9 occurs in the base 10 representation of n but not of n+1.at n=31A044752
- Numbers k such that string 8,3 occurs in the base 10 representation of k but not of k+1.at n=30A044796
- Coefficients of replicable function number 49a.at n=47A058700
- Reverse of smallest prime factor of k = largest prime factor of k+1; a(1)=1.at n=5A071392