816390889 has 2 divisors, whose sum is σ = 816390890. Its totient is φ = 816390888.

The previous prime is 816390871. The next prime is 816390899. The reversal of 816390889 is 988093618.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 771728400 + 44662489 = 27780^2 + 6683^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-816390889 is a prime.

It is not a weakly prime, because it can be changed into another prime (816390899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 408195444 + 408195445.

It is an arithmetic number, because the mean of its divisors is an integer number (408195445).

Almost surely, 2^816390889 is an apocalyptic number.

It is an amenable number.

816390889 is a deficient number, since it is larger than the sum of its proper divisors (1).

816390889 is an equidigital number, since it uses as much as digits as its factorization.

816390889 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 746496, while the sum is 52.

The square root of 816390889 is about 28572.5548210166. The cubic root of 816390889 is about 934.6149344255.

The spelling of 816390889 in words is "eight hundred sixteen million, three hundred ninety thousand, eight hundred eighty-nine".