90308021 has 2 divisors, whose sum is σ = 90308022. Its totient is φ = 90308020.

The previous prime is 90308011. The next prime is 90308069. The reversal of 90308021 is 12080309.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78127921 + 12180100 = 8839^2 + 3490^2 .

It is a cyclic number.

It is not a de Polignac number, because 90308021 - 2⁶ = 90307957 is a prime.

It is a Sophie Germain 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 (90308011) 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, 45154010 + 45154011.

It is an arithmetic number, because the mean of its divisors is an integer number (45154011).

Almost surely, 2^90308021 is an apocalyptic number.

It is an amenable number.

90308021 is a deficient number, since it is larger than the sum of its proper divisors (1).

90308021 is an equidigital number, since it uses as much as digits as its factorization.

90308021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 90308021 is about 9503.0532461941. The cubic root of 90308021 is about 448.6511394745.

The spelling of 90308021 in words is "ninety million, three hundred eight thousand, twenty-one".