“I remember once going to see him when he was ill at Putney. I had ridden in taxi cab number 1729 and remarked that the number seemed to me rather a dull one, and that I hoped it was not an unfavorable omen. “No,” Ramanujan replied, “it is a very interesting number; it is the smallest number expressible as the sum of two cubes in two different ways.” —
I love this, but I'm an engineer so I like numbers with a little dot after the first digit, followed by a x10^n. Or preferably an integer followed by a femto, pico, nano, micro, milli, kilo, Mega, Giga, or Tera.