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1722 (number)

From Wikipedia, the free encyclopedia
← 1721 1722 1723 →
Cardinalone thousand seven hundred twenty-two
Ordinal1722nd
(one thousand seven hundred twenty-second)
Factorization2 × 3 × 7 × 41
Divisors1, 2, 1722
Greek numeral,ΑΨΚΒ´
Roman numeralMDCCXXII, mdccxxii
Binary110101110102
Ternary21002103
Senary115506
Octal32728
DuodecimalBB612
Hexadecimal6BA16

1722 (one thousand seven hundred [and] twenty-two) is the natural number following 1721 and preceding 1723.[1]

In mathematics

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1722 is an even composite number that is a pronic number,[1] the product of exactly four distinct primes,[2] a 4-digit term in the continued fraction for pi,[3] and the least possible number of diagonals of simple convex polyhedron with 46 face.[4]

It is the number of 8-node graphs that are not determined by their spectrum,[5] and the number of strings of length 4 over a 7-letter alphabet that do not begin with a palindrome

1722 is most notable for being a Giuga number, specifically the third one,[6][7][8] since it is a composite number whose prime factors , 2, 3, 7, and 41, divides . This can be expressed as:

.[9]

It is the largest Giuga number with 4 prime factors.[8][10]

References

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  1. 1 2 Vanovschi, Vitalii. "Properties of the number 1722". www.numberempire.com. Retrieved 2026-09-27.
  2. ↑ Sloane, N. J. A. (ed.). "Sequence A046386 (Products of exactly four distinct primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  3. ↑ Weisstein, Eric W. "Pi Continued Fraction". mathworld.wolfram.com. Wolfram Research, Inc. Retrieved 2026-09-27.
  4. ↑ Sloane, N. J. A. (ed.). "Sequence A279019 (Least possible number of diagonals of simple convex polyhedron with n faces)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  5. ↑ Weisstein, Eric W. "Determined by Spectrum". mathworld.wolfram.com. Wolfram Research, Inc. Retrieved 2026-09-27.
  6. ↑ Koninck, Jean-Marie De (2009). Those Fascinating Numbers. American Mathematical Soc. p. 135. ISBN 978-0-8218-4807-4.
  7. ↑ Burns, Jamaris; Casey, Katherine; Gichimu, Duncan; Stinson, Kerrek (2017). "Giuga's Primality Conjecture for Number Fields". Rose-Hulman Undergraduate Mathematics Journal. 18 (1) 5. Retrieved 2026-09-27.
  8. 1 2 Weisstein, Eric W. "Giuga Number". mathworld.wolfram.com. Wolfram Research, Inc. Retrieved 2026-09-27.
  9. ↑ Borwein, D.; Borwein, J. M.; Borwein, P. B.; Girgensohn, R. (1996). "Giuga's Conjecture on Primality" (PDF). American Mathematical Monthly. 103 (1): 40–50. doi:10.2307/2975213. JSTOR 2975213. Zbl 0860.11003. Archived from the original (PDF) on 2005-05-31. Retrieved 2026-09-27.
  10. ↑ Grau, José María; Oller-Marcén, Antonio M. (2011-03-17). "Generalizing Giuga's conjecture". arXiv.org. Retrieved 2026-09-27.