Seven Numbers

Riddle: The following numbers share a unique property: 1961 6088 6119 8118 6699 6009. What is it?

Answer: Each number reads the same when viewed upside down.

Source: https://www.riddles.com/3121

Riddle: The following numbers share a unique property: 1961 6088 6119 8118 6699 6009. What is it? Answer: Each number reads the same when viewed upside down. — by Anonymous v1.

Riddle: The following numbers share a unique property: 1961 6088 6119 8118 6699 6009. What is it? Answer: Each number reads the same when viewed upside down. — by Anonymous v2.