208900009 has 4 divisors (see below), whose sum is σ = 208965316. Its totient is φ = 208834704.

The previous prime is 208900001. The next prime is 208900019. The reversal of 208900009 is 900009802.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 165379600 + 43520409 = 12860^2 + 6597^2 .

It is a cyclic number.

It is not a de Polignac number, because 208900009 - 2³ = 208900001 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 208900009.

It is not an unprimeable number, because it can be changed into a prime (208900001) 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, 27594 + ... + 34339.

It is an arithmetic number, because the mean of its divisors is an integer number (52241329).

Almost surely, 2^208900009 is an apocalyptic number.

It is an amenable number.

208900009 is a deficient number, since it is larger than the sum of its proper divisors (65307).

208900009 is an equidigital number, since it uses as much as digits as its factorization.

208900009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65306.

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 208900009 is about 14453.3736200238. The cubic root of 208900009 is about 593.3525587831.

The spelling of 208900009 in words is "two hundred eight million, nine hundred thousand, nine".