Can you find the odd number in the following?

2716, 4135, 5321 and 7145

Forwards I am heavy, backward I am not. What am I?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

In a basket of apples,
when counted in twos, there was one extra
when counted in threes, there were two extra when counted in fours, there were three extra
when counted in fives, there were four extra
when counted in sixes, there was five extra.

However, if the apples were counted in sevens, no extra apple was left. Can you calculate the minimum number of apples that were present in the basket?

If an earthquake is 1 point higher on the Richter Scale than another earthquake which is actually 10 times stronger, how much stronger would an earthquake be if it was just half a point higher on the Richter scale?

What goes up but never comes down?

My location can be determined by the below rebus.
So where am i ?

What part of the chicken has the most feathers?

If I put in one canary per cage, I have one bird too many. If I put in two canaries per cage, I have one cage too many. How many cages and canaries do I have?

With pointed fangs I sit and wait; with piercing force I crunch out fate; grabbing victims, proclaiming might; physically joining with a single bite. What am I?