221 (number)

221 (two hundred [and] twenty-one) is the natural number following 220 and preceding 222.

← 220 221 222 →
← 220 221 222 223 224 225 226 227 228 229 → List of numbers Integers ← 0 100 200 300 400 500 600 700 800 900 →
Cardinal	two hundred twenty-one
Ordinal	221st (two hundred twenty-first)
Factorization	13 × 17
Greek numeral	ΣΚΑ´
Roman numeral	CCXXI
Binary	110111012
Ternary	220123
Senary	10056
Octal	3358
Duodecimal	16512
Hexadecimal	DD16

In mathematics

Its factorization as 13 × 17 makes 221 the product of two consecutive prime numbers, the sixth smallest such product.

221 is a centered square number.

In other fields

In Texas hold 'em, the probability of being dealt pocket aces (the strongest possible outcome in the initial deal of two cards per player) is 1/221.

Sherlock Holmes's home address: 221B Baker Street.