You can 'factor' a number to find the numbers whose products make that number.
3 and 84.
One can find more information about the site 'Whose Phone Number is This?' online. Depending on which country one's number is from, there are websites where people are able to post phone numbers and who it is from. In the U.S, the website is the same name, Whose Number is This.
Find a four digit number whose digits will be reversed when multiplied by nine?
10
30
no
65, 77
140
165
67 and 99
Whose account number is this?