222 (number)

← 221 222 223 →
← 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 twenty-two
Ordinal	222nd (two hundred and twenty-second)
Factorization	2 × 3 × 37
Roman numeral	CCXXII
Binary	110111102
Ternary	220203
Quaternary	31324
Quinary	13425
Senary	10106
Octal	3368
Duodecimal	16612
Hexadecimal	DE16
Vigesimal	B220
Base 36	6636

222 (two hundred [and] twenty-two) is the natural number following 221 and preceding 223.

It is a decimal repdigit^[1] and a strobogrammatic number (meaning that it looks the same turned upside down on a calculator display).^[2] It is one of the numbers whose digit sum in decimal is the same as it is in binary.^[3]

222 is a noncototient, meaning that it cannot be written in the form n − φ(n) where φ is Euler's totient function counting the number of values that are smaller than n and relatively prime to it.^[4]

There are exactly 222 distinct ways of assigning a meet and join operation to a set of ten unlabeled elements in order to give them the structure of a lattice,^[5] and exactly 222 different six-edge polysticks.^[6]

See also

• The years CE 222 or 222 BCE.
• Room 222 (TV show)
• Bell 222 (helicopter)
• SdKfz 222, a WWII German reconnaissance vehicle
• The 222s, a Montreal punk band which took its name from a code name for co-codaprin
• 222, a comedy album by Patton Oswalt
• "222", a song by Paul McCartney on the 2-CD edition of his 2007 studio album Memory Almost Full.
• A-222 Bereg, a Russian self-propelled 130 mm coastal defence gun
• .222 Remington, a firearm cartridge

References

1. "Sloane's A010785 : Repdigit numbers, or numbers with repeated digits", The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
2. "Sloane's A018846 : Strobogrammatic numbers: numbers that are the same upside down (using calculator-style numerals)", The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
3. "Sloane's A037308 : Numbers n such that (sum of base 2 digits of n) = (sum of base 10 digits of n)", The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
4. "Sloane's A005278 : Noncototients: n such that x-phi(x) = n has no solution", The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
5. "Sloane's A006966 : Number of lattices on n unlabeled nodes", The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
6. "Sloane's A019988 : Number of ways of embedding a connected graph with n edges in the square lattice", The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.