Yes, but you have to know the index of the field:
QgsFeature::setAttribute(int field,const QVariant & attr )
You can get the fields using QgsFeature::fields and then iterate through them until you find the one you want or QgsFeature::attribute(const QString & name ) to find the field index by name.
The reason for QVariant is that the setAttribute can take Integer, Float, Date and Text types. QgsFeature.attribute(name) returns a variant also of type int if the attribute is found and something else if it can't be found.. be aware of this in your code. A try..except block would be warranted, try to convert to int and except if type is not int.