2005
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 7
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 2412
- Proper Divisor Sum (Aliquot Sum)
- 407
- 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
- 1600
- Möbius Function
- 1
- Radical
- 2005
- 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
- 112
- 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
- Number of coprime chains with largest member prime(n).at n=21A003140
- Number of ways in which n identical balls can be distributed among 5 boxes in a row such that each pair of adjacent boxes contains at least 4 balls.at n=9A005338
- 11*n^2 + 11*n + 3.at n=13A006222
- Expansion of (1+x)/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)).at n=48A008762
- Expansion of (1+x^10)/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)).at n=52A008771
- a(1)=1, a(n) = n*3^(n-1) + a(n-1).at n=5A014915
- a(n) = sum of the numbers between the two n's in A026280.at n=40A026283
- Numbers whose base-10 representation has 2 more 0's than 9's.at n=36A031498
- Number of permutations (p1,...,pn) such that 1 <= |pk - k| <= 2 for all k.at n=14A033305
- Denominators of continued fraction convergents to sqrt(386).at n=9A041733
- Numbers k such that 0 and 5 occur juxtaposed in the base-10 representation of k but not of k-1.at n=39A043220
- Numbers k such that 0 and 5 occur juxtaposed in the base-10 representation of k but not of k+1.at n=39A044000
- Numbers k such that the string 6,3 occurs in the base 7 representation of k but not of k-1.at n=45A044183
- Numbers k such that string 2,5 occurs in the base 8 representation of k but not of k-1.at n=35A044208
- Numbers n such that string 6,7 occurs in the base 9 representation of n but not of n-1.at n=26A044312
- Numbers n such that string 0,5 occurs in the base 10 representation of n but not of n-1.at n=20A044337
- Numbers n such that string 2,5 occurs in the base 8 representation of n but not of n+1.at n=35A044589
- Numbers n such that string 6,7 occurs in the base 9 representation of n but not of n+1.at n=26A044693
- Numbers n such that string 0,5 occurs in the base 10 representation of n but not of n+1.at n=20A044718
- Numbers whose base-4 representation contains exactly four 1's and two 3's.at n=9A045131