206809173845 has 16 divisors (see below), whose sum is σ = 248665697280. Its totient is φ = 165117691200.

The previous prime is 206809173803. The next prime is 206809173919. The reversal of 206809173845 is 548371908602.

It is a de Polignac number, because none of the positive numbers 2^k-206809173845 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19177355 + ... + 19188135.

It is an arithmetic number, because the mean of its divisors is an integer number (15541606080).

It is a 1-persistent number, because it is pandigital, but 2⋅206809173845 = 413618347690 is not.

Almost surely, 2^206809173845 is an apocalyptic number.

It is an amenable number.

206809173845 is a deficient number, since it is larger than the sum of its proper divisors (41856523435).

206809173845 is a wasteful number, since it uses less digits than its factorization.

206809173845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18076.

The product of its (nonzero) digits is 2903040, while the sum is 53.

The spelling of 206809173845 in words is "two hundred six billion, eight hundred nine million, one hundred seventy-three thousand, eight hundred forty-five".