2128208861 has 2 divisors, whose sum is σ = 2128208862. Its totient is φ = 2128208860.

The previous prime is 2128208843. The next prime is 2128208879. The reversal of 2128208861 is 1688028212.

It is a balanced prime because it is at equal distance from previous prime (2128208843) and next prime (2128208879).

It can be written as a sum of positive squares in only one way, i.e., 2061704836 + 66504025 = 45406^2 + 8155^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2128208861 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2128208821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1064104430 + 1064104431.

It is an arithmetic number, because the mean of its divisors is an integer number (1064104431).

Almost surely, 2^2128208861 is an apocalyptic number.

It is an amenable number.

2128208861 is a deficient number, since it is larger than the sum of its proper divisors (1).

2128208861 is an equidigital number, since it uses as much as digits as its factorization.

2128208861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24576, while the sum is 38.

The square root of 2128208861 is about 46132.5141413299. The cubic root of 2128208861 is about 1286.2875981219.

The spelling of 2128208861 in words is "two billion, one hundred twenty-eight million, two hundred eight thousand, eight hundred sixty-one".