1686840161 has 2 divisors, whose sum is σ = 1686840162. Its totient is φ = 1686840160.

The previous prime is 1686840151. The next prime is 1686840209. The reversal of 1686840161 is 1610486861.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 927507025 + 759333136 = 30455^2 + 27556^2 .

It is an emirp because it is prime and its reverse (1610486861) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1686840161 - 2¹⁴ = 1686823777 is a prime.

It is not a weakly prime, because it can be changed into another prime (1686840131) 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, 843420080 + 843420081.

It is an arithmetic number, because the mean of its divisors is an integer number (843420081).

Almost surely, 2^1686840161 is an apocalyptic number.

It is an amenable number.

1686840161 is a deficient number, since it is larger than the sum of its proper divisors (1).

1686840161 is an equidigital number, since it uses as much as digits as its factorization.

1686840161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 55296, while the sum is 41.

The square root of 1686840161 is about 41071.1597230952. The cubic root of 1686840161 is about 1190.3955940617.

The spelling of 1686840161 in words is "one billion, six hundred eighty-six million, eight hundred forty thousand, one hundred sixty-one".