janijani_

Today’s my birthday, hooray! 🥳 I’m turning 25 years old. As a Roman numeral that would be XXV and 11001 as a binary number. It is also worth noticing that 25 is

• - a square: 25 = 5^2
• - the smallest square that is a sum of two squares: 25 = 3^2 + 4^2
• - the sum of the first five(!) odd natural numbers: 25 = 1 + 3 + 5 + 7 + 9
• - an automorphic number, meaning that its square’s last digits are the same digits as the number itself: 25^2 = 625
• - a base 10 Friedman number (also the smallest base 10 Friedman number), meaning that it is the result of a non-trivial expression using all its own digits in combination with any of the four basic arithmetic operators, additive inverses, parentheses, exponentiation and concatenation: 25 = 5^2 (A bit anticlimactic, I know. For example 127 = 2^7 - 1 would be a better example of a base 10 Friedman number.)

So… Happy birthday to me? 😅