2109857 has 2 divisors, whose sum is σ = 2109858. Its totient is φ = 2109856.

The previous prime is 2109841. The next prime is 2109869. The reversal of 2109857 is 7589012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1745041 + 364816 = 1321^2 + 604^2 .

It is a cyclic number.

It is not a de Polignac number, because 2109857 - 2⁴ = 2109841 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (2102857) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1054928 + 1054929.

It is an arithmetic number, because the mean of its divisors is an integer number (1054929).

2^2109857 is an apocalyptic number.

It is an amenable number.

2109857 is a deficient number, since it is larger than the sum of its proper divisors (1).

2109857 is an equidigital number, since it uses as much as digits as its factorization.

2109857 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5040, while the sum is 32.

The square root of 2109857 is about 1452.5346811694. The cubic root of 2109857 is about 128.2579636527.

The spelling of 2109857 in words is "two million, one hundred nine thousand, eight hundred fifty-seven".