31

31
Basic Information
Cardinal Number	thirty-one
Ordinal Number	thirty first
Roman Numeral	XXXI
Greek Numeral	ΛΑ´
Factorization	31
Different Representations
Binary Form	111112
Ternary Form	10113
Quaternary Form	1334
Quinary Form	1115
Senary Form	516
Septenary Form	437
Octal Form	378
Nonary Form	349
Undecimal Form	2911
Duodecimal Form	2712
Tridecimal Form	2513
Quattuordecimal Form	2314
Quindecimal Form	2115
Hexadecimal Form	1F16
Septendecimal Form	1E17
Octodecimal Form	1D18
Novemdecimal Form	1C19
Vigesimal Form	1B20
Unvigesimal Form	1A21
Duovigesimal Form	1922
Trevigesimal Form	1823
Quattuorvigesimal Form	1724
Quinvigesimal Form	1625
Hexavigesimal Form	1526
Septenvigesimal Form	1427
Octovigesimal Form	1328
Novemvigesimal Form	1229
Trigesimal Form	1130
Untrigesimal Form	1031
Duotrigesimal Form	V32
Tretrigesimal Form	V33
Quattuortrigesimal Form	V34
Quintrigesimal Form	V35
Hexatrigesimal Form	V36
Previous	[[29]]
Current	31
Next	[[37]]

31 is a prime number from 1-100. 31 has 2 factors, 1 and 31. It is said to be a number wherein when digits are added together, they make a composite number. It is the eleventh prime number, and the eleventh prime number from 1-100. 

Proofs

• 1 can divide 31
• 2 cannot
• 3 cannot
• 4 - 28 cannot
• 29 cannot
• 30 also cannot
• 31 can divide itself

​Relationship with other odd numbers

The numbers before

• The previous odd number, 29, is a prime number.
  • There are no odd numbers between 29 and 31. As a result, they are twin primes.
• Before 29, the previous two odd numbers are 25 and 27. 25 is a square number, being 5² = 25. 27 is a cube number, being 3³ = 27.
• The prime number previous to 29 is 23.

The numbers after

• The next odd number, 33, is not a prime number. It is divisible by 3 and 11.
• The next odd number, 35, is also not a prime number. It is divisible by 5 and 7.
• 37, the odd number following 35, is a prime number.
  • 31 and 37 are six numbers apart; therefore, they are sexy primes.

Prime Numbers 1-1,000