1666139 has 2 divisors, whose sum is σ = 1666140. Its totient is φ = 1666138.

The previous prime is 1666127. The next prime is 1666151. The reversal of 1666139 is 9316661.

It is a balanced prime because it is at equal distance from previous prime (1666127) and next prime (1666151).

It is an emirp because it is prime and its reverse (9316661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1666139 - 2¹⁶ = 1600603 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1666039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833069 + 833070.

It is an arithmetic number, because the mean of its divisors is an integer number (833070).

2^1666139 is an apocalyptic number.

1666139 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666139 is an equidigital number, since it uses as much as digits as its factorization.

1666139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5832, while the sum is 32.

The square root of 1666139 is about 1290.7900681366. The cubic root of 1666139 is about 118.5505964687.

The spelling of 1666139 in words is "one million, six hundred sixty-six thousand, one hundred thirty-nine".