998807809 has 2 divisors, whose sum is σ = 998807810. Its totient is φ = 998807808.

The previous prime is 998807779. The next prime is 998807813. The reversal of 998807809 is 908708899.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 611820225 + 386987584 = 24735^2 + 19672^2 .

It is a cyclic number.

It is not a de Polignac number, because 998807809 - 2¹⁷ = 998676737 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (998807899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499403904 + 499403905.

It is an arithmetic number, because the mean of its divisors is an integer number (499403905).

Almost surely, 2^998807809 is an apocalyptic number.

It is an amenable number.

998807809 is a deficient number, since it is larger than the sum of its proper divisors (1).

998807809 is an equidigital number, since it uses as much as digits as its factorization.

998807809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2612736, while the sum is 58.

The square root of 998807809 is about 31603.9207852444. The cubic root of 998807809 is about 999.6024449709.

The spelling of 998807809 in words is "nine hundred ninety-eight million, eight hundred seven thousand, eight hundred nine".