I memorized 61 or a bit more digits probably 15 years ago. 61 digits stuck and I have them yet today. My younger brother was competing with me. He knows ~160 d

I memorized 61 or a bit more digits probably 15 years ago. 61 digits stuck and I have them yet today. My younger brother was competing with me. He knows ~160 digits. No special memory tricks - just repeatedly reading/reciting until they stuck.