840 (number)

← 839 840 841 →
Cardinal eight hundred forty
Ordinal 840th
(eight hundred and fortieth)
Factorization 23× 3 × 5 × 7
Divisors 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 15, 20, 21, 24, 28, 30, 35, 40, 42, 56, 60, 70, 84, 105, 120, 140, 168, 210, 280, 420, 840
Roman numeral DCCCXL
Binary 11010010002
Ternary 10110103
Quaternary 310204
Quinary 113305
Senary 35206
Octal 15108
Duodecimal 5A012
Hexadecimal 34816
Vigesimal 22020
Base 36 NC36

840 is the natural number following 839 and preceding 841.

It is a highly composite number,[1] a superabundant number,[2] an idoneal number,[3] and is the least common multiple of 1, 2, 3, 4, 5, 6, 7, 8.[4]

References

  1. ↑ "Sloane's A002182 : Highly composite numbers, definition (1): where d(n), the number of divisors of n (A000005), increases to a record". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  2. ↑ "Sloane's A004394 : Superabundant [or super-abundant] numbers: n such that sigma(n)/n > sigma(m)/m for all m<n, sigma(n) being the sum of the divisors of n". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  3. ↑ "Sloane's A000926 : Euler's "numerus idoneus" (or "numeri idonei", or idoneal, or suitable, or convenient numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  4. ↑ "Sloane's A003418 : Least common multiple (or LCM) of {1, 2, ..., n} for n >= 1". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
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