1687889 has 4 divisors (see below), whose sum is σ = 1929024. Its totient is φ = 1446756.

The previous prime is 1687859. The next prime is 1687909. The reversal of 1687889 is 9887861.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9887861 = 23 ⋅429907.

It is a cyclic number.

It is not a de Polignac number, because 1687889 - 2⁸ = 1687633 is a prime.

It is a d-powerful number, because it can be written as 1 + 6⁸ + 8² + 7 + 8⁴ + 8⁴ + 9 .

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1687849) 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, 120557 + ... + 120570.

It is an arithmetic number, because the mean of its divisors is an integer number (482256).

2^1687889 is an apocalyptic number.

It is an amenable number.

1687889 is a deficient number, since it is larger than the sum of its proper divisors (241135).

1687889 is an equidigital number, since it uses as much as digits as its factorization.

1687889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241134.

The product of its digits is 193536, while the sum is 47.

The square root of 1687889 is about 1299.1878232188. The cubic root of 1687889 is about 119.0642263282.

The spelling of 1687889 in words is "one million, six hundred eighty-seven thousand, eight hundred eighty-nine".