208082857921 has 9 divisors (see below), whose sum is σ = 221051273961. Its totient is φ = 195835391232.

The previous prime is 208082857909. The next prime is 208082857943. The reversal of 208082857921 is 129758280802.

The square root of 208082857921 is 456161.

It is a perfect power (a square), and thus also a powerful number.

208082857921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 7163760321 + 200919097600 = 84639^2 + 448240^2 .

It is not a de Polignac number, because 208082857921 - 2⁵ = 208082857889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (208082857901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 7741321 + ... + 7768153.

Almost surely, 2^208082857921 is an apocalyptic number.

208082857921 is the 456161-st square number.

208082857921 is the 228081-st centered octagonal number.

It is an amenable number.

208082857921 is a deficient number, since it is larger than the sum of its proper divisors (12968416040).

208082857921 is an frugal number, since it uses more digits than its factorization.

208082857921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53700 (or 26850 counting only the distinct ones).

The product of its (nonzero) digits is 1290240, while the sum is 52.

The spelling of 208082857921 in words is "two hundred eight billion, eighty-two million, eight hundred fifty-seven thousand, nine hundred twenty-one".