What numbers equal their number of letters?

In all cultures, people have made connections between letters and numbers. For example, in Chinese, numbers are considered lucky or unlucky depending on the meaning of words they sound like. The luckiest number is 8, because the mandarin word for eight, (八 pinyin: bā) sounds the same as 發, which means wealth. 

Interestingly, our head office suite number is 800, which is considered lucky because the sum of its digits 8+0+0 = 8!

In English, there are some numbers with interesting properties, but the luckiest seems to be four, which has exactly four letters, and is the only number with this property, namely to equal their number of letters.

Meanwhile, in Chinese, the same four is the unluckiest number, because 四 (pinyin sì) sounds almost the same as death (死, pinyin sǐ).

So is four lucky or unlucky? You tell me!

And finally, some interesting properties for the geekiests: 

• forty is the only number whose letters are in alphabetical order

• one is the only number whose letters are in reverse alphabetical order