208821065 has 4 divisors (see below), whose sum is σ = 250585284. Its totient is φ = 167056848.

The previous prime is 208821043. The next prime is 208821073. The reversal of 208821065 is 560128802.

208821065 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 137992009 + 70829056 = 11747^2 + 8416^2 .

It is a cyclic number.

It is not a de Polignac number, because 208821065 - 2¹⁰ = 208820041 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20882102 + ... + 20882111.

It is an arithmetic number, because the mean of its divisors is an integer number (62646321).

Almost surely, 2^208821065 is an apocalyptic number.

It is an amenable number.

208821065 is a deficient number, since it is larger than the sum of its proper divisors (41764219).

208821065 is an equidigital number, since it uses as much as digits as its factorization.

208821065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41764218.

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 208821065 is about 14450.6423732649. The cubic root of 208821065 is about 593.2778060718.

Adding to 208821065 its reverse (560128802), we get a palindrome (768949867).

The spelling of 208821065 in words is "two hundred eight million, eight hundred twenty-one thousand, sixty-five".