Converting coordinates in metres to Longitude & Latitude (CRS conversion) in OGC WKT format?

Question

I have two tools that produce output in OGC WKT format. But they look different. Could you please explain this(I am very new to GIS).

For my project I want the coordinates in the second format. Is it possible to convert from first format to second?

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Tool 1: http://dev.giscloud.com/examples/drawingtools.html

POLYGON ((16136169.435794141 -4553684.305378843,16136205.862815436 -4553671.31705568,16136219.448302884 -4553708.341241255,16136182.424117308 -4553720.433817994,16136169.435794141 -4553684.305378843))

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Tool 2: https://arthur-e.github.io/Wicket/sandbox-gmaps3.html

POLYGON((144.95369132692065 -37.81764246645652,144.9540426963016 -37.81754923679548,144.9541714423343 -37.81782468772676,144.95381470853533 -37.8179263924262,144.95369132692065 -37.81764246645652))

Answer 1

Finally found the answer with proj4js library http://proj4js.org/

var proj4 = require('proj4');

var firstProjection = 'EPSG:3857'
var cod = proj4(firstProjection).inverse([16136169.435794141, -4553684.305378843]);
console.log(JSON.stringify(cod));