31

Basic Information

Cardinal Number

thirty-one

Ordinal Number

thirty first

Roman Numeral

XXXI

Greek Numeral

ΛΑ´

Factorization

31

Standard Form

3.1 × 10¹

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

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29	31	37

31 is a prime number from 1-100. 31 has 2 factors, 1 and 31. It is the eleventh prime number, and the eleventh prime number from 1-100. The primorial of 31 is 200,560,490,130.

It is also the second pi-prime, since it makes up the first two digits of pi. 3 is the first.

Proofs[]

— 31 is divisible by 1.

— 31 is not divisible by 2-30.

— 31 is divisible by 31.

Therefore, 31 has 2 factors and is prime.

As an Exponent of Mersenne Number[]

2³¹ - 1, which is the number 2,147,483,647, is a prime number. It is the 8th Mersenne prime.

Relationship with other odd numbers[]

The numbers before[]

23 is the second previous prime number.
25 is a square number: 5² = 25
27 is a cube number: 3³ = 27
29 is the previous prime number.
- There are no odd numbers between 29 and 31. As a result, they are twin primes.

The numbers after[]

The next odd number, 33, is a composite number. It can be factored into 3 x 11.
The next odd number, 35, is also a composite number. It can be factored into 5 x 7.
37, the odd number following 35, is the next prime number.
- The difference between 37 and 31 is 6. Therefore, they are sexy primes.

Trivia[]

The cube root of 31 is an approximation of pi: ${\sqrt[{3}]{3}}1=3.14138065...$
31 is the maximum amount of days in one month. 58.3% of months have 31 days.

Prime Numbers 1-1,000

1-100
1-25	2 • 3 • 5 • 7 • 11 • 13 • 17 • 19 • 23
26-50	29 • 31 • 37 • 41 • 43 • 47
51-75	53 • 59 • 61 • 67 • 71 • 73
76-100	79 • 83 • 89 • 97

101-200
101-125	101 • 103 • 107 • 109 • 113
126-150	127 • 131 • 137 • 139 • 149
151-175	151 • 157 • 163 • 167 • 173
176-200	179 • 181 • 191 • 193 • 197 • 199

201-400
201-250	211 • 223 • 227 • 229 • 233 • 239 • 241
250-300	251 • 257 • 263 • 269 • 271 • 277 • 281 • 283 • 293
301-350	307 • 311 • 313 • 317 • 331 • 337 • 347 • 349
351-400	353 • 359 • 367 • 373 • 379 • 383 • 389 • 397

401-600
401-450	401 • 409 • 419 • 421 • 431 • 433 • 439 • 443 • 449
450-500	457 • 461 • 463 • 467 • 479 • 487 • 491 • 499
501-550	503 • 509 • 521 • 523 • 541 • 547
551-600	557 • 563 • 569 • 571 • 577 • 587 • 593 • 599

601-800
601-650	601 • 607 • 613 • 617 • 619 • 631 • 641 • 643 • 647
651-700	653 • 659 • 661 • 673 • 677 • 683 • 691
701-750	701 • 709 • 719 • 727 • 733 • 739 • 743
751-800	751 • 757 • 761 • 769 • 773 • 787 • 797

801-1,000
801-850	809 • 811 • 821 • 823 • 827 • 829 • 839
851-900	853 • 857 • 859 • 863 • 877 • 881 • 883 • 887
901-950	907 • 911 • 919 • 929 • 937 • 941 • 947
951-1000	953 • 967 • 971 • 977 • 983 • 991 • 997

31