9905221 has 2 divisors, whose sum is σ = 9905222. Its totient is φ = 9905220.

The previous prime is 9905209. The next prime is 9905239. The reversal of 9905221 is 1225099.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9641025 + 264196 = 3105^2 + 514^2 .

It is an emirp because it is prime and its reverse (1225099) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 9905221 - 2⁹ = 9904709 is a prime.

It is a super-2 number, since 2×9905221² = 196226806117682, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 9905221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9905261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4952610 + 4952611.

It is an arithmetic number, because the mean of its divisors is an integer number (4952611).

Almost surely, 2^9905221 is an apocalyptic number.

It is an amenable number.

9905221 is a deficient number, since it is larger than the sum of its proper divisors (1).

9905221 is an equidigital number, since it uses as much as digits as its factorization.

9905221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 9905221 is about 3147.2561065156. The cubic root of 9905221 is about 214.7606566774.

The spelling of 9905221 in words is "nine million, nine hundred five thousand, two hundred twenty-one".