You would still write the number "520" instead of using words. If you had to write it out fully, you would write 'quinientos veinte'
Five hundred twenty dollars.
520 is written as quinientos veinte.
520 = 52000% 5/20 = 25%
520% = 520/100 = 5 1/5 [as a mixed number] or 26/5 [as an improper fraction].
1,520,000
520,000,000 or five hundred twenty million.
23 x 5 x 13
Five hundred twenty and 00/100 dollars
520
520
520