1686985 has 4 divisors (see below), whose sum is σ = 2024388. Its totient is φ = 1349584.

The previous prime is 1686983. The next prime is 1687009. The reversal of 1686985 is 5896861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5896861 = 379 ⋅15559.

It can be written as a sum of positive squares in 2 ways, for example, as 1121481 + 565504 = 1059^2 + 752^2 .

It is a cyclic number.

It is not a de Polignac number, because 1686985 - 2¹ = 1686983 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1686983) 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 in 3 ways as a sum of consecutive naturals, for example, 168694 + ... + 168703.

It is an arithmetic number, because the mean of its divisors is an integer number (506097).

2^1686985 is an apocalyptic number.

It is an amenable number.

1686985 is a deficient number, since it is larger than the sum of its proper divisors (337403).

1686985 is an equidigital number, since it uses as much as digits as its factorization.

1686985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 337402.

The product of its digits is 103680, while the sum is 43.

The square root of 1686985 is about 1298.8398669582. The cubic root of 1686985 is about 119.0429663832.

The spelling of 1686985 in words is "one million, six hundred eighty-six thousand, nine hundred eighty-five".