A common meaning of the digits is as follows:

0. Everything or absoluteness. All
1. Individual. Aggressor. Yang.
2. Balance. Union. Receptive. Yin.
3. Communication/interaction. Neutrality.
4. Creation.
5. Action. Restlessness.
6. Reaction/flux. Responsibility.
7. Thought/consciousness.
8. Power/sacrifice.
9. Completion.
10. Rebirth.

In Chinese numerology it is:

1 —
2 二 — easy
3 三 — live
4 四 — considered unlucky since the pronunciation of 4 (sì ) sounds like the word for death or suffering (sǐ ).
5 五 — the self, me, myself, nothing, never
6 六 — easy and smooth, all the way.
7 七 — a slang/vulgar word in Cantonese.
8 八 — sudden fortune, prosperity
9 九 — long in time, a slang/vulgar word in Cantonese
10 十 — sure

See http://www.psyche.com/psyche/qbl/comparative_numerology.html

It includes the meaning of the digits according to various systems.