9905521 has 2 divisors, whose sum is σ = 9905522. Its totient is φ = 9905520.

The previous prime is 9905513. The next prime is 9905561. The reversal of 9905521 is 1255099.

9905521 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8202496 + 1703025 = 2864^2 + 1305^2 .

It is a cyclic number.

It is not a de Polignac number, because 9905521 - 2³ = 9905513 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9905561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4952760 + 4952761.

It is an arithmetic number, because the mean of its divisors is an integer number (4952761).

Almost surely, 2^9905521 is an apocalyptic number.

It is an amenable number.

9905521 is a deficient number, since it is larger than the sum of its proper divisors (1).

9905521 is an equidigital number, since it uses as much as digits as its factorization.

9905521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4050, while the sum is 31.

The square root of 9905521 is about 3147.3037667184. The cubic root of 9905521 is about 214.7628248117.

The spelling of 9905521 in words is "nine million, nine hundred five thousand, five hundred twenty-one".