90090991009 has 2 divisors, whose sum is σ = 90090991010. Its totient is φ = 90090991008.

The previous prime is 90090990959. The next prime is 90090991021. The reversal of 90090991009 is 90019909009.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55945494784 + 34145496225 = 236528^2 + 184785^2 .

It is a cyclic number.

It is not a de Polignac number, because 90090991009 - 2¹⁹ = 90090466721 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 90090991009.

It is not a weakly prime, because it can be changed into another prime (90090991049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45045495504 + 45045495505.

It is an arithmetic number, because the mean of its divisors is an integer number (45045495505).

Almost surely, 2^90090991009 is an apocalyptic number.

It is an amenable number.

90090991009 is a deficient number, since it is larger than the sum of its proper divisors (1).

90090991009 is an equidigital number, since it uses as much as digits as its factorization.

90090991009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 59049, while the sum is 46.

The spelling of 90090991009 in words is "ninety billion, ninety million, nine hundred ninety-one thousand, nine".