21845397

Appears in sequences

• Least k such that sigma(k)=m^n for some m>1.at n=24A063869
• Smallest number m such that sigma(m) is an n-almost prime.at n=24A152092
• Positions of records in A175432.at n=21A169981
• a(n) is the smallest number N such that sigma(N) is an n-th power but not a higher power, with a(n) = 0 if no such number exists.at n=25A180162
• a(n) is the smallest number k such that sigma(k) = 2^n or 0 if no such k exists.at n=25A247956
• Nonprime numbers k such that sum of the divisors of k is a power of 2.at n=32A254603