138 (number)

← 137 138 139 →
Cardinalone hundred thirty-eight
Ordinal138th
(one hundred thirty-eighth)
Factorization2 × 3 × 23
Divisors1, 2, 3, 6, 23, 46, 69, 138
Greek numeralΡΛΗ´
Roman numeralCXXXVIII, cxxxviii
Binary100010102
Ternary120103
Senary3506
Octal2128
DuodecimalB612
Hexadecimal8A16

138 (one hundred [and] thirty-eight) is the natural number following 137 and preceding 139.

Mathematics

138 is a sphenic number,[1] an Ulam number,[2] an abundant number,[3] and a square-free congruent number.[4]

Four concentric magic circles, with a magic constant of 138.

References

  1. ^ Sloane, N. J. A. (ed.). "Sequence A007304 (Sphenic numbers: products of 3 distinct primes.)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2023-07-24.
  2. ^ Sloane, N. J. A. (ed.). "Sequence A002858 (Ulam numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2023-07-24.
  3. ^ Sloane, N. J. A. (ed.). "Sequence A005101 (Abundant numbers (sum of divisors of m exceeds 2m).)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2023-07-24.
  4. ^ Sloane, N. J. A. (ed.). "Sequence A006991 (Primitive congruent numbers.)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2023-07-24.
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