1687841 has 4 divisors (see below), whose sum is σ = 1690500. Its totient is φ = 1685184.

The previous prime is 1687837. The next prime is 1687843. The reversal of 1687841 is 1487861.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1487861 = 919 ⋅1619.

It can be written as a sum of positive squares in 2 ways, for example, as 1600225 + 87616 = 1265^2 + 296^2 .

It is a cyclic number.

It is not a de Polignac number, because 1687841 - 2² = 1687837 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (1687843) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 245 + ... + 1853.

It is an arithmetic number, because the mean of its divisors is an integer number (422625).

2^1687841 is an apocalyptic number.

It is an amenable number.

1687841 is a deficient number, since it is larger than the sum of its proper divisors (2659).

1687841 is a wasteful number, since it uses less digits than its factorization.

1687841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2658.

The product of its digits is 10752, while the sum is 35.

The square root of 1687841 is about 1299.1693500079. The cubic root of 1687841 is about 119.0630976725.

The spelling of 1687841 in words is "one million, six hundred eighty-seven thousand, eight hundred forty-one".