2103809681 has 2 divisors, whose sum is σ = 2103809682. Its totient is φ = 2103809680.

The previous prime is 2103809657. The next prime is 2103809683. The reversal of 2103809681 is 1869083012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1360429456 + 743380225 = 36884^2 + 27265^2 .

It is a cyclic number.

It is not a de Polignac number, because 2103809681 - 2¹⁰ = 2103808657 is a prime.

It is a super-2 number, since 2×2103809681² = 8852030347738643522, which contains 22 as substring.

Together with 2103809683, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (2103809683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1051904840 + 1051904841.

It is an arithmetic number, because the mean of its divisors is an integer number (1051904841).

Almost surely, 2^2103809681 is an apocalyptic number.

It is an amenable number.

2103809681 is a deficient number, since it is larger than the sum of its proper divisors (1).

2103809681 is an equidigital number, since it uses as much as digits as its factorization.

2103809681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 38.

The square root of 2103809681 is about 45867.3051421162. The cubic root of 2103809681 is about 1281.3530778352.

The spelling of 2103809681 in words is "two billion, one hundred three million, eight hundred nine thousand, six hundred eighty-one".