Ben posted this on February 20, 2015 (and this link is up unlike the one in the original): https://benvitalenum3ers.wordpress.com/2015/02/20/num3er-360... Also, it's the longest such number and the only 25 digit one. This https://www.reddit.com/r/math/comments/2wl55r/fun_with_numbe... reddit thread gives you code to check.