On February 7, it is customary to celebrate Euler Number Day (“e” Day), however, such a holiday appeared recently You can come across such a name for this number as “Neperovo number” This is due to the fact that the Scottish mathematician John Napier, who was the inventor of logarithms, is also credited with creating the number e However, such a statement has no basis Since it was Euler who first introduced this notation, and it was also he who identified the twenty-three signs of this number using its representation in the form of a number series of infinite type Just like pi, e is an inexplicably recurring number in the world of mathematics It has an endless string of decimal places, starting at 2718281828, and so on This holiday is celebrated on 2/7 for the obvious reason that the date contains the same numbers as e, rounded to the nearest tenth The Euler number is a certain coefficient that describes the relationship between phenomena such as pressure force and inertial force This concept is used mainly in physics and mathematics, and plays a fairly important role in integral and differential calculus The number e in science acquired its deserved place relatively recently, however, it has already acquired quite an important meaning This relevance is primarily due to the active development of the financial sector, to which this value is directly related The person who developed the number e as the base of the natural logarithm is Euler As you know, absolutely any number can act as a logarithm, however, it is Euler’s number that has certain unique properties, thanks to which the logarithm based on it is natural The letter e was first used by Euler in 1727, and his first work using this value was published in 1736 The choice of this particular letter to denote this value is not clear at the current time Some associate it with the fact that the word exponential, that is, exponential, begins with this letter There is another assumption, according to which the letter e turned out to be the first free letter after those that were already used to denote other quantities This holiday is most popular among scientists in the field of mathematics, physics and other exact sciences who use methods of calculations with this quantity On this day, these people usually get together and share knowledge and new discoveries Various events are held to mark this day, where the most interesting topics from the history of the development of the Euler number are covered