228 (number)
From Infogalactic: the planetary knowledge core
228 (two hundred [and] twentyeight) is the natural number following 227 and preceding 229.



Cardinal  two hundred twentyeight  
Ordinal  228th (two hundred and twentyeighth) 

Factorization  2^{2}× 3 × 19  
Prime  no  
Roman numeral  CCXXVIII  
Binary  11100100_{2}  
Ternary  22110_{3}  
Quaternary  3210_{4}  
Quinary  1403_{5}  
Senary  1020_{6}  
Octal  344_{8}  
Duodecimal  170_{12}  
Hexadecimal  E4_{16}  
Vigesimal  B8_{20}  
Base 36  6C_{36} 
228 is a refactorable number,^{[1]} and a practical number.^{[2]} There are 228 matchings in a ladder graph with five rungs.^{[3]} 228 is the smallest even number n such that the numerator of the nth Bernoulli number is divisible by a nontrivial square number that is relatively prime to n.^{[4]}
References
 ↑ "Sloane's A033950 : Refactorable numbers", The OnLine Encyclopedia of Integer Sequences. OEIS Foundation.
 ↑ "Sloane's A005153 : Practical numbers", The OnLine Encyclopedia of Integer Sequences. OEIS Foundation.
 ↑ "Sloane's A030186 : a(n) = 3a(n1) + a(n2)  a(n3)", The OnLine Encyclopedia of Integer Sequences. OEIS Foundation.
 ↑ "Sloane's A090943 : Even numbers n such that N(n) is divisible by a nontrivial square, m^2, say and GCD(n,m)=1, where N(n) is the numerator of the Bernoulli number B(n)", The OnLine Encyclopedia of Integer Sequences. OEIS Foundation.