7778521

Appears in sequences

• Numbers k such that the sum of the cubes of divisors of k is a prime.at n=22A063783
• Nontrivial prime powers (A025475) which are a sum of a smaller nontrivial prime power and a perfect cube.at n=25A226232
• Numbers n such that sigma(n) and sigma(n^2) are primes.at n=7A232444
• Numbers n such that 2n-1 and sigma(n) are both primes.at n=26A249902