Can you find out which number multiplied by itself will give the output as 12345678987654321?

I’m tall when I’m young, and I’m short when I’m old. What am I?

I am quite hot but become too cold if you remove the first two letters. What am I?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

What is the word or phrase?

Who is that with a neck and no head, two arms and no hands? What is it?

What 8 letter word can have a letter taken away and it still makes a word. Take another letter away and it still makes a word. Keep on doing that until you have one letter left. What is the word?

An American nightclub called 'The Coconut Grove' had a terrible fire in which over 400 people died. A simple design flaw in the building led to a high death toll. Subsequently, regulations were changed to ensure that all public buildings throughout the country eliminated this one detail, which proved deadly. What was it?

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

What has many keys but can’t open a single lock?