You can use PATINDEX:
select PATINDEX('%[^0-9,]%', '822632,822633,822634,822635,827402,827403,827404,827405')
Select PATINDEX('%[^0-9,]%', '822632,822633')
Select PATINDEX('%[^0-9,]%', '8226326125163143146341')
Select PATINDEX('%[^0-9,]%', '822632,822633,822')
Select PATINDEX('%[^0-9,]%', '822632,822633,8243')
Select PATINDEX('%[^0-9,]%', '822632323232233,822633')
Select PATINDEX('%[^0-9,]%', '8226323,8226335612')
Select PATINDEX('%[^0-9,]%', '822632,a822633')
Select PATINDEX('%[^0-9,]%', 'a822632,a822633')
The pattern [0-9,] looks for any of 1 to 9 or comma, [^0-9,] looks for everything else. If it finds any other char it will return index>0, otherwise zero