1666597 has 2 divisors, whose sum is σ = 1666598. Its totient is φ = 1666596.

The previous prime is 1666589. The next prime is 1666607. The reversal of 1666597 is 7956661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1028196 + 638401 = 1014^2 + 799^2 .

It is an emirp because it is prime and its reverse (7956661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1666597 - 2³ = 1666589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1666507) 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, 833298 + 833299.

It is an arithmetic number, because the mean of its divisors is an integer number (833299).

2^1666597 is an apocalyptic number.

It is an amenable number.

1666597 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666597 is an equidigital number, since it uses as much as digits as its factorization.

1666597 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 68040, while the sum is 40.

The square root of 1666597 is about 1290.9674666699. The cubic root of 1666597 is about 118.5614581473.

Subtracting 1666597 from its reverse (7956661), we obtain a square (6290064 = 2508²).

The spelling of 1666597 in words is "one million, six hundred sixty-six thousand, five hundred ninety-seven".