2005521509 has 2 divisors, whose sum is σ = 2005521510. Its totient is φ = 2005521508.

The previous prime is 2005521503. The next prime is 2005521523. The reversal of 2005521509 is 9051255002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1341170884 + 664350625 = 36622^2 + 25775^2 .

It is a cyclic number.

It is not a de Polignac number, because 2005521509 - 2⁴ = 2005521493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2005521503) 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, 1002760754 + 1002760755.

It is an arithmetic number, because the mean of its divisors is an integer number (1002760755).

Almost surely, 2^2005521509 is an apocalyptic number.

It is an amenable number.

2005521509 is a deficient number, since it is larger than the sum of its proper divisors (1).

2005521509 is an equidigital number, since it uses as much as digits as its factorization.

2005521509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4500, while the sum is 29.

The square root of 2005521509 is about 44783.0493490562. The cubic root of 2005521509 is about 1261.0794287841.

The spelling of 2005521509 in words is "two billion, five million, five hundred twenty-one thousand, five hundred nine".