231 (number)

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

← 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

Mathematics

• 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

• 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 ${\displaystyle \pi }$ is approximated as ${\displaystyle {\frac {22}{7}}}$.

Religion

• 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.