840 (number)

← 839 840 841 →
List of numbers — Integers ← 0 100 200 300 400 500 600 700 800 900 →
Cardinal	eight hundred forty
Ordinal	840th (eight hundred and fortieth)
Factorization	2^3× 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.