102798809 has 2 divisors, whose sum is σ = 102798810. Its totient is φ = 102798808.

The previous prime is 102798793. The next prime is 102798811. The reversal of 102798809 is 908897201.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 98505625 + 4293184 = 9925^2 + 2072^2 .

It is an emirp because it is prime and its reverse (908897201) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 102798809 - 2⁴ = 102798793 is a prime.

It is a Sophie Germain prime.

Together with 102798811, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 102798809.

It is not a weakly prime, because it can be changed into another prime (102798209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 51399404 + 51399405.

It is an arithmetic number, because the mean of its divisors is an integer number (51399405).

Almost surely, 2^102798809 is an apocalyptic number.

It is an amenable number.

102798809 is a deficient number, since it is larger than the sum of its proper divisors (1).

102798809 is an equidigital number, since it uses as much as digits as its factorization.

102798809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72576, while the sum is 44.

The square root of 102798809 is about 10138.9747509302. The cubic root of 102798809 is about 468.4494078989.

The spelling of 102798809 in words is "one hundred two million, seven hundred ninety-eight thousand, eight hundred nine".