809499919 has 2 divisors, whose sum is σ = 809499920. Its totient is φ = 809499918.

The previous prime is 809499917. The next prime is 809499937. The reversal of 809499919 is 919994908.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 809499919 - 2¹ = 809499917 is a prime.

It is a super-2 number, since 2×809499919² = 1310580237722013122, which contains 22 as substring.

Together with 809499917, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (809499917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 404749959 + 404749960.

It is an arithmetic number, because the mean of its divisors is an integer number (404749960).

Almost surely, 2^809499919 is an apocalyptic number.

809499919 is a deficient number, since it is larger than the sum of its proper divisors (1).

809499919 is an equidigital number, since it uses as much as digits as its factorization.

809499919 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1889568, while the sum is 58.

The square root of 809499919 is about 28451.7120574492. The cubic root of 809499919 is about 931.9778767459.

The spelling of 809499919 in words is "eight hundred nine million, four hundred ninety-nine thousand, nine hundred nineteen".