Harshad number . It also has this property in octal (1729 = 3301 8 , 3 + 3 + 0 + 1 = 7) and hexadecimal (1729 = 6C1 16 , 6 + C + 1 = 19 10 ), but not in binary . 1729 has another mildly interesting property: the 1729th decimal place is the beginning of the first occurrence of all ten digits consecutively in the