1680638 has 4 divisors (see below), whose sum is σ = 2520960. Its totient is φ = 840318.

The previous prime is 1680617. The next prime is 1680643. The reversal of 1680638 is 8360861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8360861 = 2753 ⋅3037.

It is a congruent 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 as a sum of consecutive naturals, namely, 420158 + ... + 420161.

It is an arithmetic number, because the mean of its divisors is an integer number (630240).

2^1680638 is an apocalyptic number.

1680638 is a deficient number, since it is larger than the sum of its proper divisors (840322).

1680638 is an equidigital number, since it uses as much as digits as its factorization.

1680638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 840321.

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 1680638 is about 1296.3942301630. The cubic root of 1680638 is about 118.8934856515.

The spelling of 1680638 in words is "one million, six hundred eighty thousand, six hundred thirty-eight".