Repository for all of the Amazon Web Challenges attempted so far 💡
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A rising number is a positive decimal integer of which no digit is smaller than
a digit to its left. The numbers 1234 and 455567778 are both rising numbers,
while 1232 and 17880 are not.
The sum of rising numbers less than 10^3 is 60885.
What is the sum of rising numbers less than 10^1000,000,000?
The integer 351 has the property that 3 x 51 = 153, the digit-reverse of 351.
The same is true for 425322, since 42 x 5322 = 223524, and also for 57982563, since 579825 x 63 = 36528975.
Positive integers larger than 9 which have this property when written in decimal
are called cranky. The sum of all cranky integers smaller than 10^6 is
1778723.
What is the sum of all cranky integers smaller than 10^14?