Six
numeral
The kanji and the word are exactly the same. That means they share meanings as well.
Since this word is made up of a single kanji, it should use the kun'yomi reading. Numbers, as you know, are the exception to this rule. They usually use the on'yomi reading, and the on'yomi reading is the one you learned along with this kanji, meaning you should be good to go!
六円
six yen
六ポイント
six points
六ユーロ
six euros
わたしのソーシャルセキュリティナンバーには六がたくさんあります。
There are many sixes in my social security number.
このレストランには六タイプのソースがあります。
This restaurant has six types of sauce.
なんで六メートルの大きなソファがいるんですか？
Why do you need a giant six-meter sofa?