816987893 has 2 divisors, whose sum is σ = 816987894. Its totient is φ = 816987892.

The previous prime is 816987877. The next prime is 816987911. The reversal of 816987893 is 398789618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 816987889 + 4 = 28583^2 + 2^2 .

It is a cyclic number.

It is not a de Polignac number, because 816987893 - 2⁴ = 816987877 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (816987833) 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, 408493946 + 408493947.

It is an arithmetic number, because the mean of its divisors is an integer number (408493947).

Almost surely, 2^816987893 is an apocalyptic number.

It is an amenable number.

816987893 is a deficient number, since it is larger than the sum of its proper divisors (1).

816987893 is an equidigital number, since it uses as much as digits as its factorization.

816987893 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5225472, while the sum is 59.

The square root of 816987893 is about 28583.0000699717. Note that the first 4 decimals coincide. The cubic root of 816987893 is about 934.8426982365.

The spelling of 816987893 in words is "eight hundred sixteen million, nine hundred eighty-seven thousand, eight hundred ninety-three".