1681817 has 2 divisors, whose sum is σ = 1681818. Its totient is φ = 1681816.

The previous prime is 1681807. The next prime is 1681837. The reversal of 1681817 is 7181861.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1466521 + 215296 = 1211^2 + 464^2 .

It is an emirp because it is prime and its reverse (7181861) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1681817 - 2¹⁰ = 1680793 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1681807) 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, 840908 + 840909.

It is an arithmetic number, because the mean of its divisors is an integer number (840909).

2^1681817 is an apocalyptic number.

It is an amenable number.

1681817 is a deficient number, since it is larger than the sum of its proper divisors (1).

1681817 is an equidigital number, since it uses as much as digits as its factorization.

1681817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2688, while the sum is 32.

The square root of 1681817 is about 1296.8488732308. The cubic root of 1681817 is about 118.9212811779.

The spelling of 1681817 in words is "one million, six hundred eighty-one thousand, eight hundred seventeen".