Number Gossip

(Enter a number and I'll tell you everything you wanted to know about it but were afraid to ask.)

Unique Properties of 99

  • 99 is the largest number that is equal to the sum of its digits plus the product of its digits: 99 = 9 + 9 + 9 * 9
  • 99 is the smallest multi-digit palindrome that is one less than a square
  • 99 is the alphanumeric value of THIRTEEN
  • 99 is the smallest number for which the digital sum contains the same distinct digits as the digital product but the digital sum is not equal to the digital product
  • 99 is the largest 2-digit palindrome which is also palindromic in binary (submitted by Andy Edwards)

Common Properties of 99

Composite
Deficient
Evil
Lucky
Odd
Palindrome
Ulam