How is the sum of 1,821,500 Saudi Riyals to be divided among three sons and their mother, after selling a property they inherited from their deceased father?

If your father's heirs are limited to those mentioned, then your father's estate is divided as follows: your mother (his wife) receives one-eighth as a prescribed share, due to the presence of a descendant heir. Allah Almighty says: "But if you have a child, then for them [the wives] is one-eighth of what you leave." What remains after the wife's prescribed share is for the sons by way of ta'sib (residuary heirship), to be divided equally among them. The origin of the estate is eight, and it is corrected to twenty-four shares. The wife receives three shares, and each son receives seven shares.