7515217927

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=34A051281
• a(n) is the least composite x such that sigma(x) divides (x-1)^n but not (x-1)^(n-1), for n >= 2.at n=31A254352
• a(n) is the largest number k such that sigma(k) = 2^n or 0 if no such k exists.at n=33A295043
• Sphenic numbers that are the product of Mersenne primes.at n=23A346138