3648100

Appears in sequences

• Squares whose sum of divisors is a square.at n=5A008848
• Duplicate of A008848.at n=5A074387
• Numbers n such that both sigma(n) and sigma(sigma(n)) are odd numbers.at n=7A097025
• Perfect (or pure) powers pp such that sigma(pp) is also a perfect (pure) power.at n=6A128607
• Sigma-powerful numbers: powerful numbers n such that sigma(n) is also powerful. An incomplete version of A337045.at n=4A180090
• Numbers k such that both k and sigma(k)=A000203(k) are powerful, i.e., are terms of A001694.at n=15A337044
• Indecomposable sigma-powerful numbers: powerful numbers k such that sigma(k) is also powerful, but restricted to terms that are not the product of 2 terms > 1 of A337044.at n=11A337045