4205
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 11
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 5226
- Proper Divisor Sum (Aliquot Sum)
- 1021
- 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
- 3248
- Möbius Function
- 0
- Radical
- 145
- Omega Function (Ω)
- 3
- 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
- 95
- 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
- no
- Odd
- yes
Appears in sequences
- Discriminants of totally real quartic fields (see comments).at n=10A002769
- Number of nonequivalent dissections of an n-gon into n-4 polygons by nonintersecting diagonals rooted at a cell up to rotation.at n=5A003443
- Spiral sieve using Fibonacci numbers.at n=17A005623
- Coordination sequence T1 for Zeolite Code DOH.at n=40A008078
- Coordination sequence for alpha-Mn, Position Mn1.at n=17A009950
- Number of subsets of { 1, ..., n } containing an arithmetic progression of length 4.at n=13A018789
- Pseudoprimes to base 41.at n=34A020169
- a(n) = b(n) + d(n), where b(n) = (n-th Fibonacci number > 1) and d(n) = (n-th non-Fibonacci number).at n=16A023483
- n-th non-Lucas number plus Fibonacci(n + 1).at n=17A023490
- Discriminants of totally real quartic fields.at n=13A023680
- n written in fractional base 6/4.at n=23A024637
- Numbers that are the sum of 2 nonzero squares in exactly 3 ways.at n=42A025286
- Numbers that are the sum of 2 distinct nonzero squares in exactly 3 ways.at n=41A025304
- a(n) = T(n,0) + T(n,1) + ... + T(n,[ n/2 ]), T given by A026703.at n=11A026711
- a(n) = 5*n^2.at n=29A033429
- Number of different values of i^2 + j^2 + k^2 for i,j,k in [ 0,n ] (or [ -n,n ]).at n=47A034966
- Number of partitions of 5n such that cn(0,5) <= cn(1,5) = cn(4,5) <= cn(2,5) = cn(3,5).at n=9A036880
- Numbers whose base-7 representation contains exactly three 5's.at n=30A043415
- Numbers n such that replacing digits d in decimal expansion of n with d^2 yields a square.at n=50A048386
- Numbers k such that k and k-1 both have 6 divisors.at n=43A049104