291 (number)

← 290 291 292 →
← 200 210 220 230 240 250 260 270 280 290 → List of numbers Integers ← 0 100 200 300 400 500 600 700 800 900 →
Cardinal	two hundred ninety-one
Ordinal	291st (two hundred ninety-first)
Factorization	3 × 97
Divisors	1, 3, 97, 291
Greek numeral	ΣϞΑ´
Roman numeral	CCXCI, ccxci
Binary	1001000112
Ternary	1012103
Senary	12036
Octal	4438
Duodecimal	20312
Hexadecimal	12316

291 is the natural number following 290 and preceding 292.

In mathematics

• 291 is an odd composite number with two prime factors. ^[1]
• 291 is a semiprime number meaning that it has 2 prime factors. ^[2]
• 291 can be written as the sum of the nth prime plus n. It is the 52nd prime (239) plus 52. ^[3]
• 291 is one of the positions of “c” in the tribonacci word abacabaab… defined by a->ab, b->ac, c->a. ^[4]
• 291 is the sum of six 4th powers. It is the sum of 4⁴+2⁴+2⁴+1⁴+1⁴+1⁴. ^[5]

References

1. "Facts about the integer". mathworld.wolfram.com.
2. "Semiprime". mathworld.wolfram.com.
3. Sloane, N. J. A. (ed.). "SequenceA014688". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
4. Sloane, N. J. A. (ed.). "SequenceA003146(Positions of letter c in the tribonacci word abacabaabacababac... generated by a->ab, b->ac, c->a (cf. A092782))". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.
5. Sloane, N. J. A. (ed.). "SequenceA003340(Numbers that are the sum of 6 positive 4th powers)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation.