90909991009 has 2 divisors, whose sum is σ = 90909991010. Its totient is φ = 90909991008.

The previous prime is 90909990947. The next prime is 90909991013. The reversal of 90909991009 is 90019990909.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 90393429025 + 516561984 = 300655^2 + 22728^2 .

It is an emirp because it is prime and its reverse (90019990909) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 90909991009 - 2¹⁵ = 90909958241 is a prime.

It is not a weakly prime, because it can be changed into another prime (90909991079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45454995504 + 45454995505.

It is an arithmetic number, because the mean of its divisors is an integer number (45454995505).

Almost surely, 2^90909991009 is an apocalyptic number.

It is an amenable number.

90909991009 is a deficient number, since it is larger than the sum of its proper divisors (1).

90909991009 is an equidigital number, since it uses as much as digits as its factorization.

90909991009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 531441, while the sum is 55.

The spelling of 90909991009 in words is "ninety billion, nine hundred nine million, nine hundred ninety-one thousand, nine".