1666985 has 4 divisors (see below), whose sum is σ = 2000388. Its totient is φ = 1333584.

The previous prime is 1666943. The next prime is 1666991. The reversal of 1666985 is 5896661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5896661 = 41 ⋅143821.

It can be written as a sum of positive squares in 2 ways, for example, as 369664 + 1297321 = 608^2 + 1139^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666985 - 2⁸ = 1666729 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

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, 166694 + ... + 166703.

It is an arithmetic number, because the mean of its divisors is an integer number (500097).

2^1666985 is an apocalyptic number.

It is an amenable number.

1666985 is a deficient number, since it is larger than the sum of its proper divisors (333403).

1666985 is an equidigital number, since it uses as much as digits as its factorization.

1666985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333402.

The product of its digits is 77760, while the sum is 41.

The square root of 1666985 is about 1291.1177328191. The cubic root of 1666985 is about 118.5706581871.

The spelling of 1666985 in words is "one million, six hundred sixty-six thousand, nine hundred eighty-five".