1687897 has 4 divisors (see below), whose sum is σ = 1705396. Its totient is φ = 1670400.

The previous prime is 1687859. The next prime is 1687909. The reversal of 1687897 is 7987861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7987861 = 7 ⋅1141123.

It can be written as a sum of positive squares in 2 ways, for example, as 876096 + 811801 = 936^2 + 901^2 .

It is a cyclic number.

It is not a de Polignac number, because 1687897 - 2¹⁹ = 1163609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1687837) 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, 8604 + ... + 8797.

It is an arithmetic number, because the mean of its divisors is an integer number (426349).

2^1687897 is an apocalyptic number.

It is an amenable number.

1687897 is a deficient number, since it is larger than the sum of its proper divisors (17499).

1687897 is an equidigital number, since it uses as much as digits as its factorization.

1687897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17498.

The product of its digits is 169344, while the sum is 46.

The square root of 1687897 is about 1299.1909020617. The cubic root of 1687897 is about 119.0644144355.

The spelling of 1687897 in words is "one million, six hundred eighty-seven thousand, eight hundred ninety-seven".