819914509 has 2 divisors, whose sum is σ = 819914510. Its totient is φ = 819914508.

The previous prime is 819914507. The next prime is 819914533. The reversal of 819914509 is 905419918.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 672364900 + 147549609 = 25930^2 + 12147^2 .

It is a cyclic number.

It is not a de Polignac number, because 819914509 - 2¹ = 819914507 is a prime.

It is a super-2 number, since 2×819914509² = 1344519604137422162, which contains 22 as substring.

Together with 819914507, 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 (819914507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 409957254 + 409957255.

It is an arithmetic number, because the mean of its divisors is an integer number (409957255).

Almost surely, 2^819914509 is an apocalyptic number.

It is an amenable number.

819914509 is a deficient number, since it is larger than the sum of its proper divisors (1).

819914509 is an equidigital number, since it uses as much as digits as its factorization.

819914509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 116640, while the sum is 46.

The square root of 819914509 is about 28634.1493500331. The cubic root of 819914509 is about 935.9576332426.

The spelling of 819914509 in words is "eight hundred nineteen million, nine hundred fourteen thousand, five hundred nine".