Prestiging on a classic is really not worth it. As you only get 0.02% DR bonus per prestige level, assuming you get 5.6b total XP, you'll end up with a total of 10.3% DR.
But as Sprout mentioned, you'll land 933 bonds, and having a classic account with 15 prestige levels, would be quite the flex.
But to prestige under 5.6b XP? not worth the effort.