who invented the number zero?
Indian mathematician Brahmagupta
Number
The first known documented use of zero dates to AD 628, and appeared in the "Brāhmasphuṭasiddhānta", the main work of the Indian mathematician Brahmagupta. 
what is the parity of zero? The quality of an integer being even or odd—is even.
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Number [SEP] Zero
The first known documented use of zero dates to AD 628, and appeared in the "Brāhmasphuṭasiddhānta", the main work of the Indian mathematician Brahmagupta. He treated 0 as a number and discussed operations involving it, including division. By this time (the 7th century) the concept had clearly reached Cambodia as Khmer numerals, and documentation shows the idea later spreading to China and the Islamic world. Brahmagupta's "Brāhmasphuṭasiddhānta" is the first book that mentions zero as a number, hence Brahmagupta is usually considered the first to formulate the concept of zero. He gave rules of using zero with negative and positive numbers, such as "zero plus a positive number is a positive number, and a negative number plus zero is the negative number." The "Brāhmasphuṭasiddhānta" is the earliest known text to treat zero as a number in its own right, rather than as simply a placeholder digit in representing another number as was done by the Babylonians or as a symbol for a lack of quantity as was done by Ptolemy and the Romans.