2005725409 has 4 divisors (see below), whose sum is σ = 2010727620. Its totient is φ = 2000723200.

The previous prime is 2005725401. The next prime is 2005725413. The reversal of 2005725409 is 9045275002.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9045275002 = 2 ⋅4522637501.

It can be written as a sum of positive squares in 2 ways, for example, as 1473408225 + 532317184 = 38385^2 + 23072^2 .

It is a cyclic number.

It is not a de Polignac number, because 2005725409 - 2³ = 2005725401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2005725401) 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 in 3 ways as a sum of consecutive naturals, for example, 2500504 + ... + 2501305.

It is an arithmetic number, because the mean of its divisors is an integer number (502681905).

Almost surely, 2^2005725409 is an apocalyptic number.

It is an amenable number.

2005725409 is a deficient number, since it is larger than the sum of its proper divisors (5002211).

2005725409 is an equidigital number, since it uses as much as digits as its factorization.

2005725409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5002210.

The product of its (nonzero) digits is 25200, while the sum is 34.

The square root of 2005725409 is about 44785.3258221931. The cubic root of 2005725409 is about 1261.1221650301.

The spelling of 2005725409 in words is "two billion, five million, seven hundred twenty-five thousand, four hundred nine".