Can you find the odd number in the following?

2716, 4135, 5321 and 7145

What is wrong in the below Picture?

What goes up but never comes down?

Look at the below sequence of letters and tell us what the next letter should be:

O T T F F S S ?

A new clothing store has a unique method of pricing items. A vest costs $20, a tie costs $15, a blouse costs $30, and underwear costs $45. How much would pants cost?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

What is the word or phrase?

Find three whole, positive numbers that have the same answer when multiplied together as when added together.

A number with an interesting property:

When I divide it by 2, the remainder is 1.
When I divide it by 3, the remainder is 2.
When I divide it by 4, the remainder is 3.
When I divide it by 5, the remainder is 4.
When I divide it by 6, the remainder is 5.
When I divide it by 7, the remainder is 6.
When I divide it by 8, the remainder is 7.
When I divide it by 9, the remainder is 8.
When I divide it by 10, the remainder is 9.

It's not a small number, but it's not really big, either.
When I looked for a smaller number with this property I couldn't find one.

Can you find it?

I never was there, I am always to be.
You have never ever seen me, not ever you will.
Yet I am the confidence of everyone.

Who Am I?