The "beast number" 666 has many interesting properties:
a. inter alia the beast number is equal to the sum of the squares of the first k primes. Evaluate k.
b. satisfies the identity:
666=1^6-2^6+3^6
c. There are exactly two ways to insert "+" signs into the sequence 123456789 to make the sum 666,- find both.
d. and exactly one way for the sequence 987654321,- find it as well.

p and p - no software!