2105021309 has 2 divisors, whose sum is σ = 2105021310. Its totient is φ = 2105021308.

The previous prime is 2105021287. The next prime is 2105021323. The reversal of 2105021309 is 9031205012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1452372100 + 652649209 = 38110^2 + 25547^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2105021309 is a prime.

It is a super-2 number, since 2×2105021309² = 8862229422688146962, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2105021339) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1052510654 + 1052510655.

It is an arithmetic number, because the mean of its divisors is an integer number (1052510655).

Almost surely, 2^2105021309 is an apocalyptic number.

It is an amenable number.

2105021309 is a deficient number, since it is larger than the sum of its proper divisors (1).

2105021309 is an equidigital number, since it uses as much as digits as its factorization.

2105021309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 2105021309 is about 45880.5112111886. The cubic root of 2105021309 is about 1281.5990166405.

The spelling of 2105021309 in words is "two billion, one hundred five million, twenty-one thousand, three hundred nine".