231 (number)
| ||||
|---|---|---|---|---|
| Cardinal | two hundred thirty-one | |||
| Ordinal | 231st (two hundred thirty-first) | |||
| Factorization | 3 × 7 × 11 | |||
| Greek numeral | ΣΛΑ´ | |||
| Roman numeral | CCXXXI, ccxxxi | |||
| Binary | 111001112 | |||
| Ternary | 221203 | |||
| Senary | 10236 | |||
| Octal | 3478 | |||
| Duodecimal | 17312 | |||
| Hexadecimal | E716 | |||
231 (two hundred [and] thirty-one) is the natural number following 230 and preceding 232.
Mathematics
[edit]- 231 is a sphenic number. [1]
- 231 is the 21st triangular number,[2] a doubly triangular number, a hexagonal number, an octahedral number[3] and a centered octahedral number.[4]
- 231 is palindromic in base 2 (111001112).
- 231 is the number of integer partitions of 16.
- The Mertens function of 231 returns 0.[5]
In other fields
[edit]- A US gallon is defined by being exactly 231 cubic inches, the volume of a cylinder 7 inches in diameter and 6 inches tall, where is approximated as .
Religion
[edit]- 231 in the Kabbalistic text Sefer Yetzirah is identified as the number of “gates” in the Hebrew alphabet, mystical combinations of two unique letters where order is interchangeable.
References
[edit]- ^ Sloane, N. J. A. (ed.). "Sequence A007304 (sphenic number)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ^ "A000217 - OEIS". oeis.org. Retrieved 2024-11-28.
- ^ "Sloane's A005900 : Octahedral numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-24.
- ^ "Sloane's A001845 : Centered octahedral numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-24.
- ^ "Sloane's A028442 : Numbers n such that Mertens' function is zero". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-24.
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