One is the number which represents individuality and the ego. When seen in dreams, this digit may illustrate your prominent personality, your ambition, strong will and resolution to always drive home an idea/ action/ undertaking and go the whole hog on something. The digit 1 in dreams may also be a metaphor for 'being the one' - therefore for standing out due to remarkable skills, having the abilities and resources required for becoming a leader etc.
Number one as dream symbol may also represent uniqueness, originality, being different from the others. It may also stand for wholeness, unity, an illustration of the phrase 'all become one'. To be one may also mean to be on your own, being a metaphor for absolute independence and freedom of choice. All these meanings foretell good luck and happy events to follow in your waking life.
If the digit zero may represent unworthiness, the digit one stands for worthiness - be it worthiness of the self or of the others. If you have a dream in which you see number one, you may also have an increased self-esteem which is going to help you attain high goals as long as it does not become vanity and arrogance.
On the other hand, 'to be one' means to be alone and do it all on your own. As long as you deal with the situation, it may be OK, at least for the moment. But most of us may feel lonely and deserted when not having friends to rely on and people to care for us. We are 'social animals', after all, as Aristotle said and we cannot lead our lives alone.
Number one as dream image may also bear a negative significance in that which concerns lack of communication. Therefore, it may stand for your inability to express yourself, speak your mind and interact with the others.