-A "number" is sometimes used to refer to a woman. She is an attractive number.
Number is also used to refer to an item of merchandise; or a song, dance, or other musical
-"Hot" means intensely interesting.
-"Little" is a diminutive --- уменьшительное прилагательное
The expression "hot little number" can have a variety of meanings.
The girl on the cover of Playboy this month is a hot little number.
Detroit Preview: Chevrolet Aveo RS Is A Surprisingly Hot Little Number ...
“Solamente La Samba”, for instance, is a hot little number, especially notable for its spicy trumpet work.
When you want a dress that you will be able to get a lot of wear out of, this hot little number is just right for any young girl who really wants to show off her youthful side.
The Linksys Wireless ADSL Gateway is a hot little number in more ways than one. ...