If we are going to be pedantic about this (and I am a great supporter of pedantry) then I should point out that the summit of Chimborazo will never be the closest point on earth to the sun in January. The closest point will always be close to that which has the sun directly overhead (subject to local variations related to the actual heights). Being pretty much on the equator, Chimborazo will only be the closest point around its middays near the equinoxes in March and September.

But good luck on the challenge raising money for a great cause.

Chimborazo is probably the furthest point from the centre of the Earth but certainly not the highest mountain on Earth. The Earth being an oblate spheroid the actual centre is somewhat problematical. There is a strong case that the subsidiary summit of Huascaran in Peru is the furthest point from the Earths "centre".
However the International Geographical Union conference (Des Moines, IA, 1980) and ratified by the Royal Geographical Society some years later states a mountains height is the difference between it's summit and it's base. No Geographer would ever consider the centre of the Earth as a base of any mountain. The highest mountain on Earth (base to summit is Mauna Kea). Indeed the British Quiz Association recommends that quizmasters should accept Mauna Kea as an alternative answer to Everest (strictly the highest mountain above sea level), but refuses to accept Chimborazo as a correct answer.
Good luck anyway, must rush I have a pile of paper clips that need counting.

I am a member of LDWA and have signed up for a crazy challenge in January to climb CHIMBORAZO, the highest mountain on the planet, measured from the centre of the earth, raising money for two Mountain Rescue Teams in Snowdonia. This is going to be a huge physical and mental challenge so please sponsor me generously to raise vital funds for the wonderful Mountain Rescue Teams who are always there to help crazy people like me or you who love the the mountains but by accident, misfortune or stupidity may get into difficultities in Snowdonia.

https://uk.virginmoneygiving.com/HeatherBentley1

Thank you
Heather (Bentley)

https://uk.virginmoneygiving.com/HeatherBentley1