Euclid Number Calculator

Enter an integer to check if it's a Euclid number, or input a range to generate all Euclid numbers within that range.

Euclid Number Check or Generate

What is a Euclid Number?

A Euclid number is defined as \( E_n = P_n\# + 1 \), where \( P_n\# \) represents the product of the first \( n \) prime numbers. Simply put, a Euclid number is formed by adding one to the factorial of the first \( n \) primes.

Prime Factorial: The product of the first \( n \) prime numbers is referred to as \( P_n\# \). Examples include:

  • \( P_1\# = 2 \)
  • \( P_2\# = 2 \times 3 = 6 \)
  • \( P_3\# = 2 \times 3 \times 5 = 30 \)

How to Determine if a Number is a Euclid Number

  1. Input a Number: Enter the number you want to verify.
  2. Calculate Euclid Numbers: Compute \( P_n\# + 1 \) using successive primes.
  3. Compare: Check if the input number matches any of the calculated Euclid numbers.
  4. Result: If the number matches, it is a Euclid number; otherwise, it isn't.

Examples

Example 1: Is 3 a Euclid Number?

Solution:

Calculation:

\( P_1\# = 2 \)

\( E_1 = 2 + 1 = 3 \)

Result: 3 is a Euclid number.

Example 2: Is 2023 a Euclid Number?

Solution:

Calculation:

\( P_2\# = 2 \times 3 = 6 \)

\( P_3\# = 2 \times 3 \times 5 = 30 \)

\( P_4\# = 2 \times 3 \times 5 \times 7 = 210 \)

\( P_5\# = 2 \times 3 \times 5 \times 7 \times 11 = 2310 \)

Since 2310 is greater than 2023 and 2023 does not equal \( P_n\# + 1 \) for any \( n \), 2023 is not a Euclid number.

Example 3: Is 30031 a Euclid Number?

Solution:

Calculation:

\( P_2\# = 2 \times 3 = 6 \)

\( P_3\# = 2 \times 3 \times 5 = 30 \)

\( P_4\# = 2 \times 3 \times 5 \times 7 = 210 \)

\( P_5\# = 2 \times 3 \times 5 \times 7 \times 11 = 2310 \)

\( P_6\# = 2 \times 3 \times 5 \times 7 \times 11 \times 13 = 30030 \)

\( 30030 + 1 = 30031 \)

Result: 30031 is a Euclid number.