The Sun has of course more temperature than any planet, although Mercury and Venus surfaces are in the 427ºC and 462ºC respectively. It's curious that Mercury should have more since it's closer to the Sun, but the greenhouse effect due to the high CO2 content of Venus' atmosphere causes a heat boost.
The Sun breaks records even in its coldest areas with 4100K (approx. 3800ºC). The star even uses a clever mechanism to amplify power output, not in vain it consumes 620 million metric tons of hydrogen any second. So 1, 2, 3, ... it tricks the mind easily!
And, what about planet cores? Gas giants like Neptune, Jupiter, Saturn or Uranus would surpass these limits and that's true. Neptune has perhaps there about 7000ºC, Uranus 23700ºC, Saturn 27000ºC and Jupiter 54000ºC. These estimations are maybe illustrative.
Anyway, the Sun's core goes to 15.000.000ºC, and this is also pretty high to imagine.