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:
“In mathematics he was greater
Than Tycho Brahe, or Erra Pater:
For he, by geometric scale,
Could take the size of pots of ale;
Resolve, by sines and tangents straight,
If bread and butter wanted weight;
And wisely tell what hour o’ th’ day
The clock doth strike, by algebra.”
—Samuel Butler (1612–1680)
“Mathematics alone make us feel the limits of our intelligence. For we can always suppose in the case of an experiment that it is inexplicable because we don’t happen to have all the data. In mathematics we have all the data ... and yet we don’t understand. We always come back to the contemplation of our human wretchedness. What force is in relation to our will, the impenetrable opacity of mathematics is in relation to our intelligence.”
—Simone Weil (1909–1943)