Are there enough nukes to destroy the world?

Answer 1

Not even close. The largest thermonuclear bomb ever detonated was around 57 megatons. Setting off a million of those would release about as much energy as a magnitude 9.5 earthquake. Big earthquake? Yes. Destroy the earth? No way. Now, there are probably enough to kill off all higher forms of life on the surface of the Earth either from direct damage or radiation sickness. But the Earth itself would scarcely be affected.