The coords given for this cache are not the actual cache site! - they are for the Sign of the Kiwi (S 43° 36.374 E 172° 38.718), which you will need to pass through on your way to the carpark nearest to the cache.
You've all heard of the real estate business talking of prime locations. Well, here's a Prime Lo-Cache-on, a cache with coords based on prime numbers.
What you have to do is to factorise two numbers to find the real cache coordinates.
The first number 688903 is for the South coordinate, and there are three prime factors. The middle factor gives the Degrees South, the smallest factor gives the integer portion of Minutes, while the largest factor is the 3-digit fractional part of Minutes (For example, if the three factors were 29, 41, 337, then the coordinate would be S 41° 29.337).
The second number 2742884 is for the East coordinate, and here there are five prime factors. Multiply the two small ones with the 4th largest to get Degrees East, and the two remaining factors form the Minutes as above.
The cache is a small plastic container with logbook, and room for a few trading goodies.
Earthquake Update The 22 Feb earthquake has changed the landscape up here. What was once four 5-tonne boulders with one balanced on top of the biggest one, is now three boulder (a prime number no less!!), as the balancing boulder rolled 20m away. When I visited it, I was fully expecting the cache box to be squashed flat - but no, it was sitting out in the open in "prime" condition. The area is safe to visit.
Fire Update The area was devastated by the Port Hills fires, and the original cache got melted.