31 (number)
Natural number
From Wikipedia, the free encyclopedia
Mathematics
31 is a prime number, a twin prime[1] (with 29), and a Mersenne prime.[2]
In other fields
31 equal temperament is a popular microtonal tuning for musical instruments because it provides a good approximation of harmonic intervals.
January, March, May, July, August, October and December have 31 days.
31 is the international calling code for the Netherlands.
