1685789321 has 2 divisors, whose sum is σ = 1685789322. Its totient is φ = 1685789320.

The previous prime is 1685789311. The next prime is 1685789323. The reversal of 1685789321 is 1239875861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1683953296 + 1836025 = 41036^2 + 1355^2 .

It is a cyclic number.

It is not a de Polignac number, because 1685789321 - 2¹⁴ = 1685772937 is a prime.

It is a Sophie Germain prime.

Together with 1685789323, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1685789321.

It is not a weakly prime, because it can be changed into another prime (1685789323) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 842894660 + 842894661.

It is an arithmetic number, because the mean of its divisors is an integer number (842894661).

Almost surely, 2^1685789321 is an apocalyptic number.

It is an amenable number.

1685789321 is a deficient number, since it is larger than the sum of its proper divisors (1).

1685789321 is an equidigital number, since it uses as much as digits as its factorization.

1685789321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 725760, while the sum is 50.

The square root of 1685789321 is about 41058.3648115704. The cubic root of 1685789321 is about 1190.1483516765.

The spelling of 1685789321 in words is "one billion, six hundred eighty-five million, seven hundred eighty-nine thousand, three hundred twenty-one".