When Adam died, the angels washed his body with water an odd number of times, dug him a grave, and said: 'This is the tradition for Adam's children. [Al-Haakim]

لما تُوُفِّيَ آدمُ غَسَّلَتْه الملائكةُ بالماء وِتْرًا، وأَلْحَدُوا له، وقالوا: هذه سُنَّةُ آدَمَ في وَلَدِه». [صحيح.] - [رواه الطبراني والحاكم.]