2009991085 has 4 divisors (see below), whose sum is σ = 2411989308. Its totient is φ = 1607992864.

The previous prime is 2009991079. The next prime is 2009991101. The reversal of 2009991085 is 5801999002.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5801999002 = 2 ⋅2900999501.

It can be written as a sum of positive squares in 2 ways, for example, as 1518349156 + 491641929 = 38966^2 + 22173^2 .

It is a cyclic number.

It is not a de Polignac number, because 2009991085 - 2⁹ = 2009990573 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 200999104 + ... + 200999113.

It is an arithmetic number, because the mean of its divisors is an integer number (602997327).

Almost surely, 2^2009991085 is an apocalyptic number.

It is an amenable number.

2009991085 is a deficient number, since it is larger than the sum of its proper divisors (401998223).

2009991085 is an equidigital number, since it uses as much as digits as its factorization.

2009991085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 401998222.

The product of its (nonzero) digits is 58320, while the sum is 43.

The square root of 2009991085 is about 44832.9241183307. The cubic root of 2009991085 is about 1262.0155623988.

The spelling of 2009991085 in words is "two billion, nine million, nine hundred ninety-one thousand, eighty-five".