How to convert a number to binary ?

Hello and welcome, maybe you just want to know how to write a number as binary?

By adding "0b" prefix (or "B" prefix, for bytes (8 bits) only), like this:

int x = 0b0011000000111001; //binary notation for 12345
byte y = B01111011;   //binary notation for 123
byte z = 0b01111011; //also valid of course

More infos here: Binary number - Wikipedia