2009172085 has 4 divisors (see below), whose sum is σ = 2411006508. Its totient is φ = 1607337664.

The previous prime is 2009172083. The next prime is 2009172097. The reversal of 2009172085 is 5802719002.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5802719002 = 2 ⋅2901359501.

It can be written as a sum of positive squares in 2 ways, for example, as 711875761 + 1297296324 = 26681^2 + 36018^2 .

It is a cyclic number.

It is not a de Polignac number, because 2009172085 - 2¹ = 2009172083 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2009172085.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2009172083) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 200917204 + ... + 200917213.

It is an arithmetic number, because the mean of its divisors is an integer number (602751627).

Almost surely, 2^2009172085 is an apocalyptic number.

It is an amenable number.

2009172085 is a deficient number, since it is larger than the sum of its proper divisors (401834423).

2009172085 is an equidigital number, since it uses as much as digits as its factorization.

2009172085 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 401834422.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 2009172085 is about 44823.7892753390. The cubic root of 2009172085 is about 1261.8441302684.

The spelling of 2009172085 in words is "two billion, nine million, one hundred seventy-two thousand, eighty-five".