1687685 has 4 divisors (see below), whose sum is σ = 2025228. Its totient is φ = 1350144.

The previous prime is 1687669. The next prime is 1687729. The reversal of 1687685 is 5867861.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 516961 + 1170724 = 719^2 + 1082^2 .

It is a cyclic number.

It is not a de Polignac number, because 1687685 - 2⁴ = 1687669 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 168764 + ... + 168773.

It is an arithmetic number, because the mean of its divisors is an integer number (506307).

2^1687685 is an apocalyptic number.

It is an amenable number.

1687685 is a deficient number, since it is larger than the sum of its proper divisors (337543).

1687685 is an equidigital number, since it uses as much as digits as its factorization.

1687685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 337542.

The product of its digits is 80640, while the sum is 41.

The square root of 1687685 is about 1299.1093102584. The cubic root of 1687685 is about 119.0594293934.

It can be divided in two parts, 16876 and 85, that added together give a palindrome (16961).

The spelling of 1687685 in words is "one million, six hundred eighty-seven thousand, six hundred eighty-five".