1666697 has 4 divisors (see below), whose sum is σ = 1764756. Its totient is φ = 1568640.

The previous prime is 1666657. The next prime is 1666711. The reversal of 1666697 is 7966661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1301881 + 364816 = 1141^2 + 604^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666697 - 2¹⁶ = 1601161 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666607) 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 in 3 ways as a sum of consecutive naturals, for example, 49004 + ... + 49037.

It is an arithmetic number, because the mean of its divisors is an integer number (441189).

2^1666697 is an apocalyptic number.

1666697 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1666697 is a deficient number, since it is larger than the sum of its proper divisors (98059).

1666697 is an equidigital number, since it uses as much as digits as its factorization.

1666697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98058.

The product of its digits is 81648, while the sum is 41.

The square root of 1666697 is about 1291.0061967318. The cubic root of 1666697 is about 118.5638294282.

The spelling of 1666697 in words is "one million, six hundred sixty-six thousand, six hundred ninety-seven".