1686388 has 12 divisors (see below), whose sum is σ = 3219552. Its totient is φ = 766520.

The previous prime is 1686367. The next prime is 1686389. The reversal of 1686388 is 8836861.

It is a self number, because there is not a number n which added to its sum of digits gives 1686388.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1686389) by changing a digit.

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, 19120 + ... + 19207.

It is an arithmetic number, because the mean of its divisors is an integer number (268296).

2^1686388 is an apocalyptic number.

It is an amenable number.

1686388 is a deficient number, since it is larger than the sum of its proper divisors (1533164).

1686388 is a wasteful number, since it uses less digits than its factorization.

1686388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38342 (or 38340 counting only the distinct ones).

The product of its digits is 55296, while the sum is 40.

The square root of 1686388 is about 1298.6100261433. The cubic root of 1686388 is about 119.0289221888.

It can be divided in two parts, 168 and 6388, that added together give a palindrome (6556).

The spelling of 1686388 in words is "one million, six hundred eighty-six thousand, three hundred eighty-eight".