1985689 has 2 divisors, whose sum is σ = 1985690. Its totient is φ = 1985688.

The previous prime is 1985677. The next prime is 1985713. The reversal of 1985689 is 9865891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1974025 + 11664 = 1405^2 + 108^2 .

It is a cyclic number.

It is not a de Polignac number, because 1985689 - 2⁷ = 1985561 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1985639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 992844 + 992845.

It is an arithmetic number, because the mean of its divisors is an integer number (992845).

2^1985689 is an apocalyptic number.

It is an amenable number.

1985689 is a deficient number, since it is larger than the sum of its proper divisors (1).

1985689 is an equidigital number, since it uses as much as digits as its factorization.

1985689 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 155520, while the sum is 46.

The square root of 1985689 is about 1409.1447760965. The cubic root of 1985689 is about 125.6908731858.

The spelling of 1985689 in words is "one million, nine hundred eighty-five thousand, six hundred eighty-nine".