1681886 has 4 divisors (see below), whose sum is σ = 2522832. Its totient is φ = 840942.

The previous prime is 1681879. The next prime is 1681891. The reversal of 1681886 is 6881861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6881861 = 7 ⋅983123.

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, 420470 + ... + 420473.

It is an arithmetic number, because the mean of its divisors is an integer number (630708).

2^1681886 is an apocalyptic number.

1681886 is a deficient number, since it is larger than the sum of its proper divisors (840946).

1681886 is an equidigital number, since it uses as much as digits as its factorization.

1681886 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 840945.

The product of its digits is 18432, while the sum is 38.

The square root of 1681886 is about 1296.8754759035. The cubic root of 1681886 is about 118.9229074857.

The spelling of 1681886 in words is "one million, six hundred eighty-one thousand, eight hundred eighty-six".