73

73
Basic Information
Cardinal Number	seventy-three
Ordinal Number	seventy third
Roman Numeral	LXXIII
Greek Numeral	ΟΓ´
Factorization	73
Standard Form	7.3 × 101
Different Representations
Binary Form	10010012
Ternary Form	22013
Quaternary Form	10214
Quinary Form	2435
Senary Form	2016
Septenary Form	1337
Octal Form	1118
Nonary Form	819
Undecimal Form	6711
Duodecimal Form	6112
Tridecimal Form	5813
Quattuordecimal Form	5314
Quindecimal Form	4D15
Hexadecimal Form	4916
Septendecimal Form	4517
Octodecimal Form	4118
Novemdecimal Form	3G19
Vigesimal Form	3D20
Unvigesimal Form	3A21
Duovigesimal Form	3722
Trevigesimal Form	3423
Quattuorvigesimal Form	3124
Quinvigesimal Form	2N25
Hexavigesimal Form	2L26
Septenvigesimal Form	2J27
Octovigesimal Form	2H28
Novemvigesimal Form	2F29
Trigesimal Form	2D30
Untrigesimal Form	2B31
Duotrigesimal Form	2932
Tretrigesimal Form	2733
Quattuortrigesimal Form	2534
Quintrigesimal Form	2335
Hexatrigesimal Form	2136
Previous	71
Current	73
Next	79

73 is a prime number from 1-100. 73 has 2 factors, 1 and 73. It is the 21st prime number, and the 21st prime number from 1-100.

Proofs

• — 73 is divisible by 1.

• — 73 is not divisible by 2-72.

• — 73 is divisible by 73.

Therefore, 73 has two factors and is prime.

As an Exponent of Mersenne Number

2⁷³ - 1 is divisible by 439, and is therefore not a prime number.

Relationship with other odd numbers

The numbers before

• 37 is an emirp with 73.
  • Additionally, 37 is the 12th prime number and 73 is the 21st prime number.
    • 37 is related to 73 in a multitude of other ways.
• 67 is the second previous prime number.
  • The difference between 73 and 67 is 6. Therefore, they are sexy primes.
• 69 is a composite number; its prime factorization is 3 * 23.
• 71 is the previous prime number.
  • The difference between 73 and 71 is 2. Therefore, they are twin primes.

The numbers after

• 75 is the next odd number. It is a composite number; its prime factorization is 3 * 5².
• 77 is also a composite number; its prime factorization is 7 * 11.
• 79 is the next prime number.
  • The difference between 79 and 73 is 6. Therefore, they are sexy primes.

In science

• 73 is the atomic number of tantalum.

In chronology

• 73 is the amount of days in $\frac{1}{5}$ of a non-leap year.
• The 73rd day of a non-leap year is March 14, which is Pi Day.
  • The 73rd day of a leap year is March 15.

Trivia

• 73 is the smallest prime factor of the first composite generalized base 10 Fermat number: $10^{4}+1=10001=73\times 137$
• 73 is the only prime repunit in base 8 (111₈).
• 73 is one of the left-truncatable and right-truncatable primes in base 10.

Prime Numbers 1-1,000