He passed by the name of Chirakarin because he used to think long upon all matters, to remain awake for a long time, to sleep for a long time, and to take a long time in performing such acts.
चिरं स चिन्तयत्यर्थांश्चिरं जाग्रच्चिरं स्वपन्। चिरं कार्याभिपत्तिं च चिरकारी तथोच्यते॥