It is narrated from Sayyiduna Uqbah bin Amir (may Allah be pleased with him) that when the Messenger of Allah (peace and blessings be upon him) applied kohl he applied it an odd number of times, and when he cleaned himself after relieving himself he used an odd number of stones.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15005