1666349 has 4 divisors (see below), whose sum is σ = 1676736. Its totient is φ = 1655964.

The previous prime is 1666339. The next prime is 1666351. The reversal of 1666349 is 9436661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9436661 = 13 ⋅725897.

It is a cyclic number.

It is not a de Polignac number, because 1666349 - 2¹⁶ = 1600813 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666309) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4949 + ... + 5274.

It is an arithmetic number, because the mean of its divisors is an integer number (419184).

2^1666349 is an apocalyptic number.

It is an amenable number.

1666349 is a deficient number, since it is larger than the sum of its proper divisors (10387).

1666349 is a wasteful number, since it uses less digits than its factorization.

1666349 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10386.

The product of its digits is 23328, while the sum is 35.

The square root of 1666349 is about 1290.8714111018. The cubic root of 1666349 is about 118.5555769614. Note that the first 4 decimals are identical.

The spelling of 1666349 in words is "one million, six hundred sixty-six thousand, three hundred forty-nine".