140 days

= 2 x 2 x 5

= 2 x 10
= 4 x 5

= 2 + 4 + 6 + 8
= 1 + 3 + 6 + 10

A dodecahedron is a solid with 20 corners.

Human infants normally grow 20 teeth, which are replaced by 32 adult teeth as they grow up.

Twenty is a composite number, its proper divisors being 1, 2, 4, 5 and 10. Skipping 2 and adding the other divisors gives 20, hence 20 is a semiperfect number, and since it is not divisible by any of the smaller semiperfect numbers, it is a primitive semiperfect number. 20 is the smallest abundant number that is not a multiple of 3.

20 is the total number of digits on the human body, which makes it a possible candidate for a numeral system.

Twenty is the first number in an early Indian magic square of order 3.

The number 20 is used as an index in measuring visual acuity. 20/20 indicates normal vision at 20 feet, although it is commonly used to mean "perfect vision"

The number of twenty can also be called a score.

Twenty is the age of majority in Japanese tradition. Someone who is exactly twenty years old is described as hatachi

Twenty is the code for international direct dial phone calls to Egypt.

Twenty - a 1997 album by Lynyrd Skynyrd.

One of the TCP/IP ports used for File Transfer Protocol.

The ordinal adjective is vicenary.