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

Do You See It?

The first two letters signify a male, the first three letters signify a female, the first four letters signify a great, while the entire world signifies a great woman. What is the word?

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

The dirtier I get, the whiter I look. Who am I?

What breaks yet never falls, and what falls yet never breaks?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

I know there are two methods by using three time the same number with a plus(+) operator , you can make sum as 60.

One of them is 20+20+20.

whats the other way ?

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?