809999959 has 2 divisors, whose sum is σ = 809999960. Its totient is φ = 809999958.

The previous prime is 809999941. The next prime is 809999989. The reversal of 809999959 is 959999908.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 809999959 - 2¹⁷ = 809868887 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 809999894 and 809999903.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (809999929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 404999979 + 404999980.

It is an arithmetic number, because the mean of its divisors is an integer number (404999980).

Almost surely, 2^809999959 is an apocalyptic number.

809999959 is a deficient number, since it is larger than the sum of its proper divisors (1).

809999959 is an equidigital number, since it uses as much as digits as its factorization.

809999959 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21257640, while the sum is 67.

The square root of 809999959 is about 28460.4982212188. The cubic root of 809999959 is about 932.1697360582.

The spelling of 809999959 in words is "eight hundred nine million, nine hundred ninety-nine thousand, nine hundred fifty-nine".