1686240 has 72 divisors (see below), whose sum is σ = 5759208. Its totient is φ = 449280.

The previous prime is 1686239. The next prime is 1686257. The reversal of 1686240 is 426861.

It is a tau number, because it is divible by the number of its divisors (72).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 855 + ... + 2025.

It is an arithmetic number, because the mean of its divisors is an integer number (79989).

2^1686240 is an apocalyptic number.

1686240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1686240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2879604).

1686240 is an abundant number, since it is smaller than the sum of its proper divisors (4072968).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1686240 is a wasteful number, since it uses less digits than its factorization.

1686240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1192 (or 1181 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 1686240 is about 1298.5530408882. The cubic root of 1686240 is about 119.0254400333.

The spelling of 1686240 in words is "one million, six hundred eighty-six thousand, two hundred forty".