1666649 has 8 divisors (see below), whose sum is σ = 1752192. Its totient is φ = 1582240.

The previous prime is 1666627. The next prime is 1666657. The reversal of 1666649 is 9466661.

1666649 is nontrivially palindromic in base 4.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1666649 - 2⁸ = 1666393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1666619) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5204 + ... + 5514.

It is an arithmetic number, because the mean of its divisors is an integer number (219024).

2^1666649 is an apocalyptic number.

It is an amenable number.

1666649 is a deficient number, since it is larger than the sum of its proper divisors (85543).

1666649 is a wasteful number, since it uses less digits than its factorization.

1666649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 567.

The product of its digits is 46656, while the sum is 38.

The square root of 1666649 is about 1290.9876064471. The cubic root of 1666649 is about 118.5626912252.

The spelling of 1666649 in words is "one million, six hundred sixty-six thousand, six hundred forty-nine".