Echad Ushmonim Umeya - mi yodeya?

Question

Who knows one hundred eighty-one?

Please cite/link your sources, if possible. At some point at least twenty-four hours from now, I will:

• Upvote all interesting answers.

• Accept the best answer.

• Go on to the next number.

Answer 1

181 years after Yitzchak's birth, Yosef is released from the dungeon. (Gotta stretch those mi yodeya muscles)

Answer 2

If we are stretching muscles well here is another muscle stretcher that is appropriate to the time of the year we are in.

After Achashveroshes 180 day party he began another 7 day party for the people of Shushan for 7 days. This party began on the 181st day

Answer 3

Gematria of:

"פני האהל" - "The front of the Tent" (Last week's parsha - Ex. 26:9)