# 228 (number)

**228** (**two hundred [and] twenty-eight**) is the natural number following 227 and preceding 229.

| ||||
---|---|---|---|---|

Cardinal | two hundred twenty-eight | |||

Ordinal |
228th (two hundred and twenty-eighth) | |||

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 *n*th Bernoulli number is divisible by a nontrivial square number that is relatively prime to *n*.^{[4]}

## References

- ↑ "Sloane's A033950 : Refactorable numbers".
*The On-Line Encyclopedia of Integer Sequences*. OEIS Foundation. - ↑ "Sloane's A005153 : Practical numbers".
*The On-Line Encyclopedia of Integer Sequences*. OEIS Foundation. - ↑ "Sloane's A030186 : a(n) = 3a(n-1) + a(n-2) - a(n-3)".
*The On-Line 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 On-Line Encyclopedia of Integer Sequences*. OEIS Foundation.

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