题目内容：

请帮忙解释这段英文,我真不大懂!谢谢!
73, is the 21st prime number, it's mirror 37 is the 12th and it's mirror 21 is the product of multiplying, hang on to your hats, 7 and 3. In binary, 73 is a palindrome, 1001001, which backwards is 1001001, exactly the same
it's mirror 37 is the 12th and it's mirror 21 is the product of multiplying, hang on to your hats,这一句特别不懂 里面的is the 12th和hang on to you hats~更是问题中的问题~ 谢谢!期待高人详解!

优质解答

73 是第21个本数, 它的镜像数字37 是第12个质数,并且12的镜像数字21是一个乘法所得,可以立即想到,是用3和7 相乘得来的. 二进制中,73 是回文,1001001,它的镜像也是1001001,完全是一样的.
hang on to your hats,是一个英语成语,如果不捂住帽子,帽子就被吹走了.意思是很快就要捂住帽子,寓意一想就立即可以得出.

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Hi Frankpan!你什么时候在线的哦？你的英文很好，希望以后我有什么不懂的可以马上向你请教耶！谢谢你！