Ask Marilyn ® by Marilyn vos Savant is a column in Parade Magazine, published by PARADE, 711 Third Avenue, New York, NY 10017, USA. According to Parade, Marilyn vos Savant is listed in the "Guinness Book of World Records Hall of Fame" for "Highest IQ."
In her Parade Magazine column of February 25, 2001, Marilyn claims that it is easy to use a Calculator to determine that the square root of 12,345,678,987,654,321 is 111,111,111 (or that 111,111,111 x 111,111,111 is 12,345,678,987,654,321).
To check whether your calculator is really capable of handling this task, check the square root of 12,345,678,987,654,320 and 12,345,678,987,654,322, to ensure that the calculator does not report the same square root for values close to 12,345,678,987,654,321.
Readers report that many other calculators are capable of performing this calculation.