In Chinese culture, even numbers are generally considered auspicious.
Tips
culture
Even numbers (偶数) are considered lucky in Chinese culture because they come in pairs — 成双成对 (to come in pairs) is associated with good fortune and marriage. Gift-giving often favors even numbers.
memory
偶 also means 'in pairs' or 'accidental/even' — think of a married couple (夫妇) as a pair. 偶数 = paired numbers = even numbers.