21103

Appears in sequences

• Number of n-node rooted trees of height 5.at n=14A000342
• Numbers k such that sigma(phi(k)) - phi(sigma(k)) is nonzero and divisible by sigma(k), that is A065395(k)/A000203(k) is a nonzero integer.at n=21A092588
• 4-Smith numbers.at n=21A103125
• Numbers n whose sum of anti-divisors is a permutation of their digits.at n=33A258786
• Numbers k such that sigma(k) - k - 1 is a perfect number.at n=8A293992