Convert from yoctometer to palmo [Spanish]

Unit Definition (yoctometer)
The yoctometre (or yoctometer), symbol: ym, is a decimal fraction of a metre, from the International System of Units. One yoctometre is 1x10-24 (1e-24) in scientific notation. Very small!

Unit Definition (palmo [Spanish])
The palmo is a traditional unit of distance in Spain and Portugal. The traditional Spanish palmo equals 9 pulgadas or 1/4 vara: this is about 20.9 centimeters in Spain and a little more than that in Spanish Latin America. Under the metric system in Spain, the palmo is an informal unit equal to 20 centimeters. These units are based on the width of a person's outstretched hand, from the tip of the thumb to the tip of the little finger, a definition identical to that of the English span.