The product of two consecutive prime numbers is 437. The difference between these two prime numbers is:
4
Since \(\sqrt{437} \approx 20.9\), one prime factor lies below 21 and the other above it.
Testing primes below 21: 437 ÷ 19 = 23, so 437 = 19 × 23.
19 and 23 are consecutive primes (no prime lies between them, as 20, 21 and 22 are composite). Difference = 23 – 19 = 4.
Check: 19 × 23 = 19 × 20 + 19 × 3 = 380 + 57 = 437.
Hence, 4.
How many numbers from 1 to 30 are coprime with 30?
The sum of prime numbers upto 75 is:
What is the least number that should be added to 91 so that the result is coprime with 60?
Express 486 as a product of powers of prime factors.
Let p, q, r and s be positive natural numbers having three exact factors including 1 and the number itself. If q > p and both are two-digit numbers, and r > s and both are one-digit numbers, then the value of the expression \(\frac{p-q-1}{r-s}\) is:
Find the greatest three-digit number which is a multiple of 8.
The sum of three consecutive multiples of 7 is 840. The smallest of these multiples is:
If 2160 = 2 a × 3 b × 5 c , then the value of 3 a × 2 -b × 5 -c will be –