What does the following BrainBat signifies?

ABCDEFGHIJKLMNOPQRSTUVWYZ

QQQQQQQQQQQQQQQQQQQQQQQQQ.

O_er_t_o_

Complete the missing letters of the given word.

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?

Seven Robbers robbed a bank and hide the coins in a lonely place.
They decide to divide the money equally the next morning. Two greedy robbers decided to cheat the others and reach the place at night. They equally divided the coins between them, one coin left. So they called another robber and then they decided to divide equally among the three. Sadly again one coin left. The same thing happened to the 4th 5th and the 6th robber.
However, when the 7th robber reached in the morning, they can divide the coins equally.

How many coins were there in total?

What has one letter and starts with an E?

I am white when I am dirty, and black when I am clean. What am I?

I have no life, but I can die. What am I?

Before Mount Everest was discovered, what was the highest mountain in the world?

If you say my name, I will no longer exist. What am I?

The more you take me, the more you leave me behind.
Who Am I?