*www.pcmag.com/article2/0,1759,1647333,00.aspThere are no 4xxx models because the number 4 is considered unlucky in parts of Asia.
In Mandarin Chinese, the word for 4 and the word for death *sound* similar, although they are different words. Nonetheless, in general they are considered unlucky....
Additionally, the numbers 6 and 8 are considered especially lucky here in mainland China.
Most significantly, any number that ends with an 8 is considered auspicious or prosperous.
...Hence, you will notice that a huge number of phones here in China are released with China-specific model numbers.
For example, the SE T610 and T630 are released as T618 and T628 respectively.