According to Wikipedia
Some autistic savants can:
- memorize facts, numbers, license plates, maps, and extensive lists of sports and weather statistics
- mentally note and then recall perfectly a very long sequence of music, numbers, or speech
- do exceptionally fast arithmetic, including prime factorization
- precisely estimating distances and angles by sight, calculating the day of the week for any given date over the span of tens of thousands of years, and being able to accurately gauge the passing of time without a clock