50 000 or
50,000, the same as international standard.
Reference: 出版物上数字用法的规定 (General rules for writing numerals in publications)
8 Multidigit integers and decimals:
8.1 Segmentations for multidigit integers and decimals written in Arabic numerals
8.1.1 Segmentation rules for professional scientific publications: from the decimal point, towards the left and the right, make every three digits a group; the width of the gap between two adjacent groups should be 1/4 of a Chinese character width (or 1/2 of an Arabic numeral width).
示例：2 748 456 3.141 592 65
8.1.2 For non-"professional scientific publications", if it is difficult to use "quarter space", the traditional segment comma "," is acceptable. Decimal part should not be segmented. Integers less than 4 digits can be either segmented or not segmented.
示例：2,748,456 3.14159265 8703
Edit by Stan:
If following 8.1.1, then the
四分空(quarter space) should be used according to the standard. Unfortunately, the standard hasn't exactly defined which space should be used. The list of spaces can be found in wiki. And practically, when rendering NOT by a monospaced font, I suggest using
- U+2005 Four-Per-Em Space, or
- U+202F Narrow No-Break Space
for the "quarter space". Specially, the "Narrow No-Break Space" is for the intention of not breaking a digit number.
Rendering results with mixed font
宋体+Calibri via Microsoft Word are as follows:
and for the line-breaking case (text aligning setting:
*Note that in the "Narrow No-Break Space" case, no matter how you edit the content, the number won't be break into two lines.
BTW, you can use the
Alt and the numeric keypad to input the special space, like