44

44 = 2² x 11.

44 is the smallest number that is the sum of a reversible pair of non-palindromic primes: 13 + 31 = 44.

44 is the first number such that it and the next number are the product of a prime and another distinct prime squared: 44 = 2² x 11 and 45 = 3² x 5.

44 is the maximum number of regions into which the plane can be divided by seven circles.


44 is the atomic number of the chemical element ruthenium.

Source: Number Gossip