209840337205 has 32 divisors (see below), whose sum is σ = 265555005408. Its totient is φ = 158970470400.

The previous prime is 209840337167. The next prime is 209840337209. The reversal of 209840337205 is 502733048902.

It can be written as a sum of positive squares in 16 ways, for example, as 80523142756 + 129317194449 = 283766^2 + 359607^2 .

It is a de Polignac number, because none of the positive numbers 2^k-209840337205 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (209840337209) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3160429 + ... + 3226141.

It is an arithmetic number, because the mean of its divisors is an integer number (8298593919).

Almost surely, 2^209840337205 is an apocalyptic number.

It is an amenable number.

209840337205 is a deficient number, since it is larger than the sum of its proper divisors (55714668203).

209840337205 is a wasteful number, since it uses less digits than its factorization.

209840337205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66217.

The product of its (nonzero) digits is 362880, while the sum is 43.

The spelling of 209840337205 in words is "two hundred nine billion, eight hundred forty million, three hundred thirty-seven thousand, two hundred five".