231 (number)

← 230 231 232 →
← 230 231 232 233 234 235 236 237 238 239 → List of numbers ; Integers ; ← 0 100 200 300 400 500 600 700 800 900 →
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

Last updated January 07, 2025

231 (two hundred [and] thirty-one) is the natural number following 230 and preceding 232.

Mathematics

231 is a sphenic number.
231 is the 21st triangular number,^[1] a doubly triangular number, a hexagonal number, an octahedral number ^[2] and a centered octahedral number.^[3]
231 is palindromic in base 2 (11100111₂).
231 is the number of integer partitions of 16.
The Mertens function of 231 returns 0.^[4]

Related Research Articles

21 (twenty-one) is the natural number following 20 and preceding 22.

31 (thirty-one) is the natural number following 30 and preceding 32. It is a prime number.

37 (thirty-seven) is the natural number following 36 and preceding 38.

46 (forty-six) is the natural number following 45 and preceding 47.

100 or one hundred is the natural number following 99 and preceding 101.

1000 or one thousand is the natural number following 999 and preceding 1001. In most English-speaking countries, it can be written with or without a comma or sometimes a period separating the thousands digit: 1,000.

300 is the natural number following 299 and preceding 301.

360 is the natural number following 359 and preceding 361.

400 is the natural number following 399 and preceding 401.

500 is the natural number following 499 and preceding 501.

700 is the natural number following 699 and preceding 701.

600 is the natural number following 599 and preceding 601.

800 is the natural number following 799 and preceding 801.

900 is the natural number following 899 and preceding 901. It is the square of 30 and the sum of Euler's totient function for the first 54 positive integers. In base 10, it is a Harshad number. It is also the first number to be the square of a sphenic number.

2000 is a natural number following 1999 and preceding 2001.

5000 is the natural number following 4999 and preceding 5001. Five thousand is, at the same time, the largest isogrammic numeral, and the smallest number that contains every one of the five vowels in the English language.

7000 is the natural number following 6999 and preceding 7001.

8000 is the natural number following 7999 and preceding 8001.

20,000 is the natural number that comes after 19,999 and before 20,001.

40,000 is the natural number that comes after 39,999 and before 40,001. It is the square of 200.

References

↑ "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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[1] "A000217 - OEIS". oeis.org. Retrieved 2024-11-28.

[2] "Sloane's A005900 : Octahedral numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-24.

[3] "Sloane's A001845 : Centered octahedral numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-24.

[4] "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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