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Number

2

2 — The Only Even Prime

2 is a prime, even, a calendar year.

Two is the smallest and only even prime number. Every other prime is odd, since any larger even number is divisible by 2.

Sources https://en.wikipedia.org/wiki/2
Catalan Number Curated Deficient Number Factorial Fibonacci Harshad / Niven Lucas Narcissistic / Armstrong Power of Two Prime Pronic / Oblong Squarefree

Properties

Parity
Even
Digit count
1
Digit sum
2
Digital root
2
Palindrome
Yes
Divisor count
2
σ(n) — sum of divisors
3

Primality

2 is prime. It has exactly two divisors: 1 and itself.

Divisors & multiples

All divisors (2)
1 · 2
Aliquot sum (sum of proper divisors): 1
Factor pairs (a × b = 2)
1 × 2
First multiples
2 · 4 · 6 · 8 · 10 · 12 · 14 · 16 · 18 · 20

Representations

In words
two
Ordinal
2nd
Roman numeral
II
Binary
10
Octal
2
Hexadecimal
2

Also seen as

Prime neighborhood

Adjacent primes:

  • Next prime: 3 (gap of 1)
ASCII character

As an ASCII codepoint, 2 is control character (0x02). ASCII control character.

Hex color
#000002
RGB(0, 0, 2)
IPv4 address

As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.2.