1686864 has 40 divisors (see below), whose sum is σ = 4410432. Its totient is φ = 555520.

The previous prime is 1686857. The next prime is 1686871. The reversal of 1686864 is 4686861.

It is an interprime number because it is at equal distance from previous prime (1686857) and next prime (1686871).

It is a nude number because it is divisible by every one of its digits.

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 7 ways as a sum of consecutive naturals, for example, 5269 + ... + 5579.

2^1686864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1686864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2205216).

1686864 is an abundant number, since it is smaller than the sum of its proper divisors (2723568).

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

1686864 is a wasteful number, since it uses less digits than its factorization.

1686864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 435 (or 429 counting only the distinct ones).

The product of its digits is 55296, while the sum is 39.

The square root of 1686864 is about 1298.7932860929. The cubic root of 1686864 is about 119.0401201727.

The spelling of 1686864 in words is "one million, six hundred eighty-six thousand, eight hundred sixty-four".