2105257309 has 2 divisors, whose sum is σ = 2105257310. Its totient is φ = 2105257308.

The previous prime is 2105257279. The next prime is 2105257331. The reversal of 2105257309 is 9037525012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1901396025 + 203861284 = 43605^2 + 14278^2 .

It is a cyclic number.

It is not a de Polignac number, because 2105257309 - 2¹⁹ = 2104733021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2105257379) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1052628654 + 1052628655.

It is an arithmetic number, because the mean of its divisors is an integer number (1052628655).

Almost surely, 2^2105257309 is an apocalyptic number.

It is an amenable number.

2105257309 is a deficient number, since it is larger than the sum of its proper divisors (1).

2105257309 is an equidigital number, since it uses as much as digits as its factorization.

2105257309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18900, while the sum is 34.

The square root of 2105257309 is about 45883.0830372154. The cubic root of 2105257309 is about 1281.6469094360.

The spelling of 2105257309 in words is "two billion, one hundred five million, two hundred fifty-seven thousand, three hundred nine".