If there’s an in a permanent’s mana cost, X is 0 when determining its mana value.

You can cycle a card even if it has a triggered ability from cycling that won’t have a legal target. This is because the cycling ability and the triggered ability are separate. This also means that if either ability is countered (with Disallow, for example), the other ability will still resolve.

Triggered abilities from cycling a card and the cycling ability itself aren’t spells. Effects that interact with spells (such as that of Cancel) won’t affect them.

Some cards with cycling have an ability that triggers when you cycle them, and some cards have an ability that triggers whenever you cycle any card or discard any card. These triggered abilities resolve before you draw from the cycling ability.