99900221 has 2 divisors, whose sum is σ = 99900222. Its totient is φ = 99900220.

The previous prime is 99900191. The next prime is 99900253. The reversal of 99900221 is 12200999.

It is an a-pointer prime, because the next prime (99900253) can be obtained adding 99900221 to its sum of digits (32).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 99900025 + 196 = 9995^2 + 14^2 .

It is a cyclic number.

It is not a de Polignac number, because 99900221 - 2¹⁰ = 99899197 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99930221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49950110 + 49950111.

It is an arithmetic number, because the mean of its divisors is an integer number (49950111).

Almost surely, 2^99900221 is an apocalyptic number.

It is an amenable number.

99900221 is a deficient number, since it is larger than the sum of its proper divisors (1).

99900221 is an equidigital number, since it uses as much as digits as its factorization.

99900221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 99900221 is about 9995.0098048976. The cubic root of 99900221 is about 464.0044542899.

The spelling of 99900221 in words is "ninety-nine million, nine hundred thousand, two hundred twenty-one".