五二零除不尽三
[wŭ èr líng chú bù jĭn sān]
520 (five two zero) is often used to express 'I love you' in Chinese, where the pronunciation of these numbers sounds similar to the phrase for 'I love you'. This username means that love (or I love you) cannot be evenly divided by three, which symbolizes something that is incompleteness or unrequited love.