You know my name (look up the number)

Seeing as how most of us seem to have nicely survived the ominous (or would it be "Omen"ous?) date of 6/6/06, you may be wondering what other special numbers are out there. Turns out that pretty much every number under 10,000 has at least a few interesting characteristics. Below are a couple of sites exploring them.

What's Special About This Number? is the prettier of the two, with the nice color gradations going down the list. Some of the numbers are missing in their under-10,000 list, though.

Example: 1214 is a number whose product of digits is equal to its sum of digits.

Number Gossip, while not as polychromatic, will definitely give you several unique properties for every single number under 10,000 that you enter.

Example: Your number 1514 has the following properties: even, composite, deficient, odious, square-free, Ulam.

Your number is very special! 1514 has the following unique property: 1514 is the smallest 4-digit number whose square (2292196) and cube (3470384744) use different digits.

Cool Numbers takes a slightly different tack, asking you to type in a US currency serial number and they will tell you how "cool" it is according to the "Universal Coolness Index". Criteria used to determine the UCI include things like whether the number is palindromic, whether it is a number in the Fibonacci Sequence, whether each digit is a multiple of 3, etc.

Example: The number you entered was 81147403.

This number is almost cool. It has a Universal Coolness Index of 81.0%

# 81147403 is a prime number! Only 5.8% of 8-digit numbers are prime.

# 81147403's digits sum to 28. In 18% of 8-digit numbers, the digits sum to at most 28.

(Cool Numbers link via The Presurfer)



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