Acanthocalycium glaucum is commonly known as ‘Red Tom Thumb’. It can reach up to the height of 15 cm and belongs to the Cactaceae family. Having an origin in Bolivia, this summer-dormant plant is a solitary flat globular shape to a briefly elongated cactus. 

Growth Rate
Acanthocalycium glaucum has a slow growth rate. 
Flowering
The Acanthocalycium genus is well-known for its blooms. The cacti bloom in the spring and continue to bloom until the summer, producing orange flowers.
Watering and Feeding
Acanthocalycium genus plants require moderate watering and should be watered every three to four days during the summer. Reduce watering to once a week or less in the winter. Do not overwater.
Soil
Well-drained soil is ideal for the Red tom thumb cactus. Repotting is best done early in the growing season (spring) or late in the season (summer). 
Hardiness
This attractive plant is not frost-hardy. It has a frost tolerance of - 4° C (24.8° F) and belongs to the hardiness zone of 9b to 11.
Light
Acanthocalycium glaucum, like many other cacti, thrives in full sun. Place them in an open, airy area that receives full sun exposure throughout the day.
Propagation
The cactus can be grown from seed. Growing cactus from seed can be a thrilling experience as you watch the tiny seedlings change appearance so quickly.
The Red tom thumb cactus is the best succulent for your home as well as office. This beautiful plant will make you fall in love with them. 
Some of the information in this description has been found at desert-tropicals.com, llifle.com and cactus-art.biz