P.S
The wallet prompted me to install an update before sending the transaction and I'm pretty sure it was official electrum-btc website.
Check your browsing history if it's actually
electrum.org or
https://github.com/spesmilo/electrum/.
That's to know the reason why you've been hacked, but with this:
the transaction is already confirmed
Transaction id 1cdc45c6f92430d021f387af6564353cb90281da4ee8e1e9721387ad05874c45
You won't be able to reverse the transaction.
For the validity of the address, read this:
https://en.bitcoin.it/wiki/Address(
the 1st paragraph is enough).