lucky and unlucky number combinations

Would the number 15 be considered lucky or unlucky in China (Cantonese)? Also, would the number 415 be considered lucky or unlucky? I ask because I read somewhere that the number 5 sounds like the word for "not" (or "no"), and that 1 sounds like the word for "true." So would 415 be interpreted to mean "death not true" (or something like that)?