1688861 has 2 divisors, whose sum is σ = 1688862. Its totient is φ = 1688860.

The previous prime is 1688857. The next prime is 1688887.

1688861 is nontrivially palindromic in base 10.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1651225 + 37636 = 1285^2 + 194^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 1688861 - 2² = 1688857 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1688161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 844430 + 844431.

It is an arithmetic number, because the mean of its divisors is an integer number (844431).

2^1688861 is an apocalyptic number.

It is an amenable number.

1688861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1688861 is an equidigital number, since it uses as much as digits as its factorization.

1688861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18432, while the sum is 38.

The square root of 1688861 is about 1299.5618492400. The cubic root of 1688861 is about 119.0870770054.

The spelling of 1688861 in words is "one million, six hundred eighty-eight thousand, eight hundred sixty-one".