999998789 has 2 divisors, whose sum is σ = 999998790. Its totient is φ = 999998788.

The previous prime is 999998777. The next prime is 999998801. The reversal of 999998789 is 987899999.

It is a balanced prime because it is at equal distance from previous prime (999998777) and next prime (999998801).

It can be written as a sum of positive squares in only one way, i.e., 614544100 + 385454689 = 24790^2 + 19633^2 .

It is an emirp because it is prime and its reverse (987899999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 999998789 - 2⁸ = 999998533 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999998689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499999394 + 499999395.

It is an arithmetic number, because the mean of its divisors is an integer number (499999395).

Almost surely, 2^999998789 is an apocalyptic number.

It is an amenable number.

999998789 is a deficient number, since it is larger than the sum of its proper divisors (1).

999998789 is an equidigital number, since it uses as much as digits as its factorization.

999998789 is an evil number, because the sum of its binary digits is even.

The product of its digits is 238085568, while the sum is 77.

The square root of 999998789 is about 31622.7574540868. The cubic root of 999998789 is about 999.9995963332. Note that the first 3 decimals are identical.

The spelling of 999998789 in words is "nine hundred ninety-nine million, nine hundred ninety-eight thousand, seven hundred eighty-nine".