1687009 has 2 divisors, whose sum is σ = 1687010. Its totient is φ = 1687008.

The previous prime is 1686983. The next prime is 1687033. The reversal of 1687009 is 9007861.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1440000 + 247009 = 1200^2 + 497^2 .

It is an emirp because it is prime and its reverse (9007861) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1687009 - 2¹⁵ = 1654241 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1687039) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 843504 + 843505.

It is an arithmetic number, because the mean of its divisors is an integer number (843505).

2^1687009 is an apocalyptic number.

It is an amenable number.

1687009 is a deficient number, since it is larger than the sum of its proper divisors (1).

1687009 is an equidigital number, since it uses as much as digits as its factorization.

1687009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 1687009 is about 1298.8491059396. The cubic root of 1687009 is about 119.0435309047.

It can be divided in two parts, 16 and 87009, that added together give a square (87025 = 295²).

The spelling of 1687009 in words is "one million, six hundred eighty-seven thousand, nine".