2128109857 has 2 divisors, whose sum is σ = 2128109858. Its totient is φ = 2128109856.

The previous prime is 2128109779. The next prime is 2128109897. The reversal of 2128109857 is 7589018212.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2120049936 + 8059921 = 46044^2 + 2839^2 .

It is a cyclic number.

It is not a de Polignac number, because 2128109857 - 2⁷ = 2128109729 is a prime.

It is not a weakly prime, because it can be changed into another prime (2128109897) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1064054928 + 1064054929.

It is an arithmetic number, because the mean of its divisors is an integer number (1064054929).

Almost surely, 2^2128109857 is an apocalyptic number.

It is an amenable number.

2128109857 is a deficient number, since it is larger than the sum of its proper divisors (1).

2128109857 is an equidigital number, since it uses as much as digits as its factorization.

2128109857 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 80640, while the sum is 43.

The square root of 2128109857 is about 46131.4410895649. The cubic root of 2128109857 is about 1286.2676518352.

The spelling of 2128109857 in words is "two billion, one hundred twenty-eight million, one hundred nine thousand, eight hundred fifty-seven".