Mathematics
19 is the 8th smallest prime number. The sequence continues 23, 29, 31, 37...
19 is the seventh Mersenne prime exponent.
19 is the aliquot sum of two odd discrete semiprimes, 65 and 77 and is the base of the 19-aliquot tree.
19 is a centered triangular number, centered hexagonal number and a Heegner number.
You can make the number 19 by adding or subtracting but not multiplying (whole numbers), 19 can also be made by division.
The only non-trivial normal magic hexagon contains 19 hexagons (the other being 1).
19 is the first number with more than one digit that can be written from base 2 to base 19 using only the digits 0 to 9; the other number is 20.
Read more about this topic: 19 (number)
Famous quotes containing the word mathematics:
“It is a monstrous thing to force a child to learn Latin or Greek or mathematics on the ground that they are an indispensable gymnastic for the mental powers. It would be monstrous even if it were true.”
—George Bernard Shaw (1856–1950)
“... though mathematics may teach a man how to build a bridge, it is what the Scotch Universities call the humanities, that teach him to be civil and sweet-tempered.”
—Amelia E. Barr (1831–1919)