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 639

  • 639 is the smallest number that is the sum of the first several primes and is congruent with 3 modulo 4
  • 639 is the sum of the first 20 primes

Common Properties of 639

Composite
Deficient
Evil
Lucky
Odd