819631609 has 2 divisors, whose sum is σ = 819631610. Its totient is φ = 819631608.

The previous prime is 819631573. The next prime is 819631621. The reversal of 819631609 is 906136918.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 415018384 + 404613225 = 20372^2 + 20115^2 .

It is a cyclic number.

It is not a de Polignac number, because 819631609 - 2¹¹ = 819629561 is a prime.

It is not a weakly prime, because it can be changed into another prime (819631649) 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, 409815804 + 409815805.

It is an arithmetic number, because the mean of its divisors is an integer number (409815805).

Almost surely, 2^819631609 is an apocalyptic number.

It is an amenable number.

819631609 is a deficient number, since it is larger than the sum of its proper divisors (1).

819631609 is an equidigital number, since it uses as much as digits as its factorization.

819631609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69984, while the sum is 43.

The square root of 819631609 is about 28629.2090180641. The cubic root of 819631609 is about 935.8499745088.

The spelling of 819631609 in words is "eight hundred nineteen million, six hundred thirty-one thousand, six hundred nine".