819491 has 2 divisors, whose sum is σ = 819492. Its totient is φ = 819490.

The previous prime is 819487. The next prime is 819493. The reversal of 819491 is 194918.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 819491 - 2² = 819487 is a prime.

It is a Sophie Germain prime.

Together with 819493, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (819493) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 409745 + 409746.

It is an arithmetic number, because the mean of its divisors is an integer number (409746).

2⁸¹⁹⁴⁹¹ is an apocalyptic number.

819491 is a deficient number, since it is larger than the sum of its proper divisors (1).

819491 is an equidigital number, since it uses as much as digits as its factorization.

819491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 32.

The square root of 819491 is about 905.2574219525. The cubic root of 819491 is about 93.5796455972.

The spelling of 819491 in words is "eight hundred nineteen thousand, four hundred ninety-one".