1668739 has 2 divisors, whose sum is σ = 1668740. Its totient is φ = 1668738.

The previous prime is 1668727. The next prime is 1668743. The reversal of 1668739 is 9378661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1668739 - 2¹⁵ = 1635971 is a prime.

It is not a weakly prime, because it can be changed into another prime (1668539) 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, 834369 + 834370.

It is an arithmetic number, because the mean of its divisors is an integer number (834370).

2^1668739 is an apocalyptic number.

1668739 is a deficient number, since it is larger than the sum of its proper divisors (1).

1668739 is an equidigital number, since it uses as much as digits as its factorization.

1668739 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 54432, while the sum is 40.

The square root of 1668739 is about 1291.7968106479. The cubic root of 1668739 is about 118.6122302537.

The spelling of 1668739 in words is "one million, six hundred sixty-eight thousand, seven hundred thirty-nine".