1680005 has 8 divisors (see below), whose sum is σ = 2024952. Its totient is φ = 1338048.

The previous prime is 1679981. The next prime is 1680013. The reversal of 1680005 is 5000861.

It can be written as a sum of positive squares in 4 ways, for example, as 36481 + 1643524 = 191^2 + 1282^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1680005 - 2²⁰ = 631429 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 779 + ... + 1991.

It is an arithmetic number, because the mean of its divisors is an integer number (253119).

2^1680005 is an apocalyptic number.

It is an amenable number.

1680005 is a deficient number, since it is larger than the sum of its proper divisors (344947).

1680005 is a wasteful number, since it uses less digits than its factorization.

1680005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1495.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 1680005 is about 1296.1500684720. The cubic root of 1680005 is about 118.8785569901.

Adding to 1680005 its reverse (5000861), we get a palindrome (6680866).

The spelling of 1680005 in words is "one million, six hundred eighty thousand, five".