1073602561

Appears in sequences

• Sum of divisors of n, sigma(n) (A000203), is a power of number of divisors of n, d(n) (A000005).at n=30A051281
• Numbers k such that sigma(usigma(k)) is prime.at n=8A063103
• Semiprimes that are a product of Mersenne primes.at n=23A144482
• Semiprimes that are a product of distinct Mersenne primes.at n=18A144856
• a(n) = (2^(n+4)-1)*(2^n-1).at n=13A165130
• Products of 2 successive Mersenne primes.at n=4A165223
• Numbers k such that sigma(sigma(k)) is prime.at n=7A247838
• a(n) is the largest number k such that sigma(k) = 2^n or 0 if no such k exists.at n=30A295043
• a(1) = 1; for n > 1, a(n) is the smallest number m such that sigma(m) = tau(m)^n or 0 if no such m exists.at n=14A349006