Number Gossip

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Unique Properties of 840

  • 840 is the smallest number divisible by 1 through 8
  • 840 is the smallest number n such that σ(n) = 15φ(n)
  • 840 is the smallest area of exactly three Pythagorean triangles
  • 840 is the smallest number n such that nτ(n)>4prime(n)
  • 840 is the smallest number n such that the multiplicative group modulo n is the direct product of 5 cyclic groups
  • 840 is the smallest number that is both unitary pseudoperfect and nonunitary pseudoperfect

Common Properties of 840

Abundant
Apocalyptic power
Composite
Even
Evil
Practical