1680389 has 4 divisors (see below), whose sum is σ = 1684524. Its totient is φ = 1676256.

The previous prime is 1680377. The next prime is 1680401. The reversal of 1680389 is 9830861.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (1680377) and next prime (1680401).

It can be written as a sum of positive squares in 2 ways, for example, as 1399489 + 280900 = 1183^2 + 530^2 .

It is a cyclic number.

It is not a de Polignac number, because 1680389 - 2⁴ = 1680373 is a prime.

It is a d-powerful number, because it can be written as 1 + 6⁸ + 8 + 0 + 3⁵ + 8³ + 9 .

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1680319) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1382 + ... + 2295.

It is an arithmetic number, because the mean of its divisors is an integer number (421131).

2^1680389 is an apocalyptic number.

It is an amenable number.

1680389 is a deficient number, since it is larger than the sum of its proper divisors (4135).

1680389 is an equidigital number, since it uses as much as digits as its factorization.

1680389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4134.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 1680389 is about 1296.2981910039. The cubic root of 1680389 is about 118.8876136870.

The spelling of 1680389 in words is "one million, six hundred eighty thousand, three hundred eighty-nine".