Neptune has the longest orbital revolution, taking 164.8 yrs to go about the Sun. The dwarf planet Pluto used to hold the record taking 248 years to circle the Sun.
That is Uranus.
Neptune.
Mercury is the shortest and Neptune is the longest
Mars.
If it takes as long as that it must be an outer planet.
Pluto has the longest REVOLUTION period Venus has the longest ROTATION period
The gas giant that has the longest revolution is the planet Neptune.
Neptune.
The planet that has the shortest period of revolution is Mercury, which is 88 days. The planet with the longest revolution is Neptune, which is 165 years. Earth's revolution is the third shortest.
Technically, since Pluto is no longer a planet, but a dwarf planet, Uranus is the planet that takes the longest to orbit the sun.
Neptune takes the longest as it is the farthest away.
If you mean revolution on it axis (spin/day length) rather than orbital period, then the answer is the planet Mercury, where time between sunrises is roughly 176 Earth days.