Kim Jong-un celebrates his birthday

Kim Jong-un turns 33 on today, and from the North Korean leader's perspective, he has plenty to celebrate: Everyone's talking about him again.

After several years of being overshadowed by the more imminent threat of the Islamic State and jockeying with Iran for the title of scariest nuclear regime, North Korea is back on the international agenda.

Governments around the world rushed to condemn Wednesday's nuclear test regardless of whether it involved a hydrogen bomb, as Pyongyang claimed, or an atomic device in line with its three previous tests - and the UN Security Council called an emergency meeting.

In the United States, presidential hopefuls piled on with denunciations of Kim. Hillary Clinton called him a "bully," Marco Rubio said he was a "lunatic," and Ted Cruz dubbed him a "megalomaniacal maniac."

Kim, like his father, Kim Jong Il, is often viewed as a caricature: a rotund man with a bad haircut and a worse standard outfit, who spews invective at the outside world while watching basketball games in his luxurious palaces.

The Kims have a habit of using their weapons program as a bargaining chip, launching missiles and detonating nuclear devices so they can try to extract rewards from the international community for not doing so again. This is a pattern North Korea has repeated for more than 20 years.

Analysts are split on whether this week's test is a sign that Pyongyang wants to return to negotiations, despite its repeated assertions that the world must now accept it as a nuclear state, or an indication that it has entirely given up on the prospect of talks.