1686109 has 2 divisors, whose sum is σ = 1686110. Its totient is φ = 1686108.

The previous prime is 1686071. The next prime is 1686119. The reversal of 1686109 is 9016861.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1322500 + 363609 = 1150^2 + 603^2 .

It is a cyclic number.

It is not a de Polignac number, because 1686109 - 2¹⁵ = 1653341 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1686119) 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, 843054 + 843055.

It is an arithmetic number, because the mean of its divisors is an integer number (843055).

2^1686109 is an apocalyptic number.

It is an amenable number.

1686109 is a deficient number, since it is larger than the sum of its proper divisors (1).

1686109 is an equidigital number, since it uses as much as digits as its factorization.

1686109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 1686109 is about 1298.5025991503. The cubic root of 1686109 is about 119.0223576851.

The spelling of 1686109 in words is "one million, six hundred eighty-six thousand, one hundred nine".