The Birthday of Paul Erdős (1913)

Paul Erdős was the most prolific mathematician in history (over 1,500 papers). He travelled incessantly, living out of a suitcase, collaborating with hundreds. He coined the ‘Erdős number’ – your distance via co‑authors to Erdős (his number 0, co‑authors number 1, etc.). He offered cash prizes for problems (typically $1,000 for a ‘significant’ solution). He was also a central figure in combinatorics, number theory, and graph theory, proving the Erdős–Szekeres theorem and many results on prime gaps. He never married, had no home, and gave away almost all his earnings.