1678889 has 2 divisors, whose sum is σ = 1678890. Its totient is φ = 1678888.

The previous prime is 1678883. The next prime is 1678891. The reversal of 1678889 is 9888761.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1525225 + 153664 = 1235^2 + 392^2 .

It is an emirp because it is prime and its reverse (9888761) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1678889 is a prime.

It is a Sophie Germain prime.

Together with 1678891, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a plaindrome in base 10.

It is not a weakly prime, because it can be changed into another prime (1678883) 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, 839444 + 839445.

It is an arithmetic number, because the mean of its divisors is an integer number (839445).

2^1678889 is an apocalyptic number.

It is an amenable number.

1678889 is a deficient number, since it is larger than the sum of its proper divisors (1).

1678889 is an equidigital number, since it uses as much as digits as its factorization.

1678889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 193536, while the sum is 47.

The square root of 1678889 is about 1295.7194912480. The cubic root of 1678889 is about 118.8522281286.

The spelling of 1678889 in words is "one million, six hundred seventy-eight thousand, eight hundred eighty-nine".