Post date: Feb 7, 2019 1:32:31 PM
The minimum sum of 3 digit-primes that use each non-zero digit exactly once (149 + 263 + 587).
999 is a Kaprekar number and a Harshad number.
Any multiple of 999 can be separated in groups of 3 digits from the ones position. The sum of the groups will be 999 (you may need to iterate the process).