2128208821 has 2 divisors, whose sum is σ = 2128208822. Its totient is φ = 2128208820.

The previous prime is 2128208813. The next prime is 2128208843. The reversal of 2128208821 is 1288028212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1081686321 + 1046522500 = 32889^2 + 32350^2 .

It is a cyclic number.

It is not a de Polignac number, because 2128208821 - 2³ = 2128208813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2128208861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1064104410 + 1064104411.

It is an arithmetic number, because the mean of its divisors is an integer number (1064104411).

Almost surely, 2^2128208821 is an apocalyptic number.

It is an amenable number.

2128208821 is a deficient number, since it is larger than the sum of its proper divisors (1).

2128208821 is an equidigital number, since it uses as much as digits as its factorization.

2128208821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8192, while the sum is 34.

The square root of 2128208821 is about 46132.5137077962. The cubic root of 2128208821 is about 1286.2875900632.

The spelling of 2128208821 in words is "two billion, one hundred twenty-eight million, two hundred eight thousand, eight hundred twenty-one".