What number should Shenzhen social security enter to be useful?

Legal analysis: Before 20th. According to the relevant regulations, if employees join the company after the 20th of the current month, they can't buy the social security of the current month, because Shenzhen social security is deducted on the 20th of each month, and they can buy the social security of the current month if they join the company before the 20th.

Legal basis: Article 2 of the Social Insurance Law of People's Republic of China (PRC) The state establishes social insurance systems such as basic old-age insurance, basic medical insurance, industrial injury insurance, unemployment insurance, maternity insurance, etc., to protect citizens' right to get material help from the state and society according to law in case of old age, illness, industrial injury, unemployment and maternity.