1980 (number)

Last updated
← 197919801981 →
Cardinal one thousand nine hundred eighty
Ordinal 1980th
(one thousand nine hundred eightieth)
Factorization 22 × 32 × 5 × 11
Divisors 1, 2, 3, 4, 5, 6, 9, 10, 11, 12, 15, 18, 20, 22, 30, 33, 36, 44, 45, 55, 60, 66, 90, 99, 110, 132, 165, 180, 198, 220, 330, 396, 495, 660, 990, 1980
Greek numeral ,ΑϠΠ´
Roman numeral MCMLXXX, mcmlxxx
Binary 111101111002
Ternary 22011003
Senary 131006
Octal 36748
Duodecimal 119012
Hexadecimal 7BC16

1980 is the natural number following 1979 and preceding 1981.

Mathematics

1980 is a pronic number, [1] a highly abundant number, [2] an e-perfect number [3] and a coreful perfect number. [4] Not only is it highly abundant, but it also has a greater aliquot sum than any smaller number. [5]

1980 is the fourth number with 36 divisors. [6] It forms an amicable triple with 2016 and 2556, since σ(1980) = σ(2016) = σ(2556) and 6552 = 1980 + 2016 + 2556. [7]

References

  1. ↑ Sloane, N. J. A. (ed.). "SequenceA002378(Oblong (or promic, pronic, or heteromecic) numbers)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  2. ↑ Sloane, N. J. A. (ed.). "SequenceA002093(Highly abundant numbers)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  3. ↑ Sloane, N. J. A. (ed.). "SequenceA054979(e-perfect numbers: numbers k such that the sum of the e-divisors (exponential divisors) of k equals 2*k.)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  4. ↑ Sloane, N. J. A. (ed.). "SequenceA307958". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  5. ↑ Sloane, N. J. A. (ed.). "SequenceA034090(Numbers k whose sum of proper divisors exceeds that of all smaller numbers)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  6. ↑ Sloane, N. J. A. (ed.). "SequenceA175746(Numbers with 36 divisors)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
  7. ↑ Sloane, N. J. A. (ed.). "SequenceA125490". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.


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