“Absolutely perfect“, this year 2025 ? This is in fact the expression used on his blog by mathematics professor Jérôme Cottanceau. Far from being a joke, this “incredible” characteristic of 2025 is obviously linked to numbers, to mathand the particularity of the number 2025. What surprises do we observe when we break it down?
2025, like 1936 and… 2116!
2025 is indeed a perfect squarethat is to say the result of the multiplication of 45 by itself (45×45). A rather rare mathematical feature, since the last perfect square dates back to the year 1936 (44×44), and the next ones will take place in 2116 (46×46) and 2209 (47×47). People born before 2016 and under the age of 88 will therefore certainly experience their only perfect square in 2025.
In addition to this particularity of the calendar, two other astonishing calculationscarried out by this teacher at the Léonard-de-Vinci high school in Montaigu-Vendée, allowing a result equal to 2025 to be obtained. First curiosity: 2025 is the sum of the cubes of the numbers 1 to 9. 1³ + 2³ + 3³ + 4³ + 5³ + 6³ + 7³ + 8³ + 9³ = 2025. A calculation given by the professor in a video available below.
Another curiosity: if you add up all the numbers from 1 to 9, then multiply this total by itself, you also get the current year. So : (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9) x (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9) = 45 x 45 = 2025. Amazing mystery of numerology.
The legacy of the Greeks
This is the Greek mathematician Nicomacheus of Gerasius who discovered this second curiosity, not seen since 1296, a year corresponding to the square of the sum of the numbers 1 to 8. To relive such an event, we will now have to wait 1000 yearssince the square of the sum of the numbers from 1 to 10 will take us to… 3025!
Jérôme Cottanceau himself admits: in addition to an elegant demonstration, a legacy of Greek arithmetic, this mathematical beauty has absolutely no use. But mathematicians are very attached to the astonishing properties of numbers, which also fascinate the curious.
Some will see, for example, a sign linked to numerology: the addition of the numbers that make up 2025 (2 + 0 + 2 + 5) gives the number 9symbol of culmination, of renewal. A sort of decisive chapter, the opening of a path to wisdom. We promise, we will take stock at the end of the year!
Article references:
Romanesco cabbages, laughing cow and curvilinear integrals. Jérôme Cottanceau’s Blog.
The year 2025 is a mathematical marvel, this professor explains why. HuffPost.
Perfect square, sum of cubes… Why 2025 fascinates mathematicians. The Parisian.
