Fun fact: ∞ is even

Posted by Michał ‘mina86’ Nazarewicz on 1st of April 2021

Some people find it surprising that zero is an even number. Turns out it’s such a controversial point that Wikipedia’s article on the subject has nearly 5000 words and 75 citations. That’s ten times as long as an entry on toast sandwich which is clearly a more important topic. On the other hand perhaps the confusion is to be expected considering that for centuries zero has been judged an odd digit (if a digit at all). Regardless, zero being even is not news and this is not what this post is about.

Rather, I wish to share another bit of knowledge. As it turns out, infinity is even. Who would have thought! As the working group for the C programming language (SC22 WC14) explains in C99 rationale, ‘all large positive floating-point values are even integers’.

There you go. Next time your Maths teacher asks what’s -42 to infinite power go ahead and exclaim with conviction that it’s plus infinity! The teacher will fail you of course (and rightfully so) unless you’re so lucky that they turn out to secretly be an expert on IEEE 754 standard.