How to read Diode Numbering System
Although the first number represents the number of junctions in the device and the next letter (or two) represent the device type, the last four work as a serial number and do not carry any information directly. You need to look at a table to get the specific information about the device. In some circumstances, you may notice patterns in the numbering, like the 1N400X series matches the 1N539X series in that the last number indicates Vr but they don't use the same number to indicate that rating. In the case of the previously mentioned series, both series happen to use the number 1 as the last digit to represent a Vr = 50 V device, but once you get to the number 4, things progress differently. Some series start with the number 0 as the first number in the series, where others use the number 1 as the first. So, you can't really use that serial number to say anything about the ratings on the device. You need to look at the datasheet for the specific device series.
There is a table on Wikipedia, but you should verify accuracy with the datasheets.
Wikipedia Page for 1N400X