1666669 has 4 divisors (see below), whose sum is σ = 1676160. Its totient is φ = 1657180.

The previous prime is 1666657. The next prime is 1666711. The reversal of 1666669 is 9666661.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 1666669 - 2⁷ = 1666541 is a prime.

It is a super-2 number, since 2×1666669² = 5555571111122, which contains 22 as substring.

It is a Duffinian number.

1666669 is a lucky number.

It is a plaindrome in base 10.

It is a congruent number.

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

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4477 + ... + 4834.

It is an arithmetic number, because the mean of its divisors is an integer number (419040).

2^1666669 is an apocalyptic number.

It is an amenable number.

1666669 is a deficient number, since it is larger than the sum of its proper divisors (9491).

1666669 is an equidigital number, since it uses as much as digits as its factorization.

1666669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9490.

The product of its digits is 69984, while the sum is 40.

The square root of 1666669 is about 1290.9953524316. The cubic root of 1666669 is about 118.5631654791.

The spelling of 1666669 in words is "one million, six hundred sixty-six thousand, six hundred sixty-nine".