Fascinating. My ErdÅ‘s number is 4. According to wikipedia, the median ErdÅ‘s number amongst all working mathematicians at the turn of the millennium is 5 and the average is 4.64. In this case, being below average is good. Here is how it happened: Paul ErdÃ¶s coauthored with Janos Galambos who coauthored with Eugene Seneta who coauthored with Serge Dubuc (my thesis cosupervisor).