1678993 has 2 divisors, whose sum is σ = 1678994. Its totient is φ = 1678992.

The previous prime is 1678979. The next prime is 1679009. The reversal of 1678993 is 3998761.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1617984 + 61009 = 1272^2 + 247^2 .

It is a cyclic number.

It is not a de Polignac number, because 1678993 - 2⁵ = 1678961 is a prime.

It is not a weakly prime, because it can be changed into another prime (1678093) 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, 839496 + 839497.

It is an arithmetic number, because the mean of its divisors is an integer number (839497).

2^1678993 is an apocalyptic number.

It is an amenable number.

1678993 is a deficient number, since it is larger than the sum of its proper divisors (1).

1678993 is an equidigital number, since it uses as much as digits as its factorization.

1678993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 43.

The square root of 1678993 is about 1295.7596227696. The cubic root of 1678993 is about 118.8546822072.

The spelling of 1678993 in words is "one million, six hundred seventy-eight thousand, nine hundred ninety-three".