1666279 has 2 divisors, whose sum is σ = 1666280. Its totient is φ = 1666278.

The previous prime is 1666271. The next prime is 1666297. The reversal of 1666279 is 9726661.

Together with next prime (1666297) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1666279 - 2³ = 1666271 is a prime.

1666279 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1666271) 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, 833139 + 833140.

It is an arithmetic number, because the mean of its divisors is an integer number (833140).

2^1666279 is an apocalyptic number.

1666279 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666279 is an equidigital number, since it uses as much as digits as its factorization.

1666279 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27216, while the sum is 37.

The square root of 1666279 is about 1290.8442973496. The cubic root of 1666279 is about 118.5539168437.

The spelling of 1666279 in words is "one million, six hundred sixty-six thousand, two hundred seventy-nine".