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As of August 2017, the largest known Prime number is 2^74,207,281 − 1, a number with 22,338,618digits.

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Q: How long is the largest known prime number?
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What is the largest composite digit?

The largest single digit composite number is 9. The largest prime number is 17 million digits long. The definition of a composite number is any number that has at least one positive divisor other than one or the number itself (it is not a prime number). The largest composite digit is therefore longer than the largest prime number by at leaf +1.


What is the largest 3-digit number that only has 2 and 5 as prime factors?

The only number that ONLY has two and five as factors is 10, which has two digits, so there are no numbers that are three digits long and ONLY have two and five for factors. However, if you are asking what the largest three digit number that has two and five for factors, it would be the largest three digit number with ten as a factor, as ten the the LCM of two and five, and that would be 390.


What is the largest three digit number if no digits may be repeated?

The largest number with no repeated digits is 9,876,543,210 although it is 10 digits long, the largest 3 digit number with no repeated digits is 987


Is a number even when the largest digit in the number is even?

No, in order for the number to be even, the last number must be a multiple of 2. It doesn't matter what the largest number is as long as the last number is a multiple of two.


What is the longest consecutive composite number?

There is no largest composite number. Nor is there a largest sequence of consecutive composite numbers - those sequences can become arbitrarily long.

Related questions

How long is the longest prime number?

The largest known prime number is 17,425,170, although technically, there is no largest possible prime number. To this day, mathematicians are still searching for higher prime numbers.


What is the biggest known prime?

M sub 39 is the largest prime number. I can't write it out because it is over 40,000 numbers long.


What is the largest composite digit?

The largest single digit composite number is 9. The largest prime number is 17 million digits long. The definition of a composite number is any number that has at least one positive divisor other than one or the number itself (it is not a prime number). The largest composite digit is therefore longer than the largest prime number by at leaf +1.


What is the highest prime factor?

As of 2013, the largest known prime number is 257,885,161 − 1. It is 17,425,170 digits long. There is no largest prime, there is only the largest number that has been shown to be prime. There has been a mathematical proof that no number can be the largest prime since the time of Euclid. No matter how large a prime number is discovered, a larger one exists. The problem is that the larger the primes get, the rarer they get. Just picking a number at random with 20 million digits will almost certainly produce a nonprime number. That is why there are various formulas to give good guesses for prime numbers. The formula for Mersenne numbers Mn=2n − 1. Not all Mersenne numbes are prime, but they have been shown to be good guesses. 257,885,161 − 1 is the 48th Mersenne prime discovered. A Mersenne prime is named after the French monk Marin Mersenne who studied prime numbers in the 17th century.This Mersenne prime and the previous 9 record primes were discovered by the "Great Internet Mersenne Prime Search" (GIMPS), a distributed computing project on the Internet operated just for the purpose of finding Mersenne prime.


Can there be prime numbers over 1 million?

Yes. In fact the largest known prime contains 9,808,358 decimal digits. http://primes.utm.edu/largest.html Slump Virus MOGWAII: Actually, as of this year (2010), the largest prime number found is 12 978 189 decimal digits long. Want to download it?


How long did it take to find the largest prime number?

It has not yet been discovered because numbers are infinite


Write a easy program to print the sum of squares of alternative prime numbers?

It is not possible to print the sum of alternate prime numbers because prime numbers are infinite and, therefore, alternate prime numbers are also infinite. Thus the only way you can write such a program is if you set an upper limit on the largest prime you wish to consider. That limit will be determined by the maximum sum you can store in a built-in integral type which is ULLONG_MAX. In other words, you must stop generating prime numbers if the sum would overflow. We achieve this by storing ULLONG_MAX and then decrement by each alternate prime until the next prime is greater than the remainder. The largest sum is therefore ULLONG_MAX minus that remainder. The following program demonstrates this. #include<io.sys> #include<limits.h> #include<math.h> // Forward declarations of required functions (see definitions below) bool is_prime (unsigned long long); unsigned long long next_prime (unsigned long long); int main (void) { unsigned long long remainder = ULLONG_MAX; unsigned long long prime = 2; // 2 is the first prime (same as next_prime (0) or next_prime (1)) unsigned long long largest = prime; // keep track of largest prime in sum while (prime<=remainder) { // test for overflow! remainder -= prime; // subtract the prime largest = prime; // update largest sum prime = next_prime (next_prime (prime)); // skip the next prime and get the next } printf ("The sum of alternate primes is:\n%u", ULLONG_MAX - remainder); printf ("The largest prime in the sum is: %u\n", largest); return 0; } // Returns true if num is prime, otherwise false bool is_prime (unsigned long long num) { if (num<2) return false; // 2 is the first prime if (!(num%2) return num==2; // 2 is the only even prime unsigned long long max_factor = (unsigned long long) sqrt (num); for (unsigned long long factor=3; factor<=max_factor; factor+=2) // test all odd factors >= 3 if (!(num%factor)) return false; // factor is prime factor of num, so num is non-prime return true; // num has no prime factors, so num is prime } // Returns the next prime greater than num. unsigned long long next_prime (unsigned long long num) { while (!is_prime (++num)); return num; }


If a number has only two factors itself and 1 what is it called?

Prime Numbers. 1 isn't prime, 2 is. so is 3,5,7,11,13,17,19...


What happens when you find the the GCF with prime factorization but there is only one number in common?

As long as the other number is not a multiple of the prime number, the GCF will always be 1.


How do you find the largest square factor of whole numbers?

The long but fool-proof way is to find the complete prime factorisation of the number. Then group all the factors into pairs, rejecting any that cannot be paired. The product of the numbers that are left is the largest square factor.


What is the largest 3-digit number that only has 2 and 5 as prime factors?

The only number that ONLY has two and five as factors is 10, which has two digits, so there are no numbers that are three digits long and ONLY have two and five for factors. However, if you are asking what the largest three digit number that has two and five for factors, it would be the largest three digit number with ten as a factor, as ten the the LCM of two and five, and that would be 390.


What do the largest teeth known to mankind belong to?

Sperm Whales have the largest teeth known to man kind males can have teeth up to 20.5 inches long