What is the maximum value of Easting in UTM coordinates?
In many websites I found the answer of maximum value is about 834000 meters, but if you convert some of these coordinates below the value will be much higher than that.
Latitude: 61.44 Longitude: 25.40 --> Converted in UTM: Sector: 35 V Northing: 414668 Easting: 6812844
Latitude: -47.04 Longitude: -73.48 --> Converted: Sector: 18 G Northing: 615471 Easting: 4789269
You are correct about the maximum value, you just have the easting and northing backwards.
In your first example, the easting is 414668 m and the northing is 6812844 m. The convention is eastings first. You can think of UTM coordinates as $(x, y)$ pairs, and they are sometimes labelled as such. Here's the conversion offered by one converter:
As you say, eastings are usually less than 834 000 m, and more than 160 000 m.
Note than some UTM zones are non-standard widths. Also, you will sometimes see coordinates referenced to some neighbouring zone, which isn't a good idea but is sometimes convenient, so the numbers can be unexpectedly large. Lastly: be aware that in the US you may sometimes come across UTM coordinates in other units, such as feet. Horrible.
The circumference of the Earth at the equator is ~40,075km. Given that each UTM Zone is 6 degrees spaced in Longitude, there are then 60 UTM Zones around the globe. Each Zone is thus 40,075/60 or ~668km at the equator (less towards the poles). The central Easting for each Zone is 500km, therefore the max and min Easting for each Zone is 500+668/2 (834km) and 500-668/2 (166km). These max and min Easting values clearly diminish at higher Lattitudes.
