6666689 has 2 divisors, whose sum is σ = 6666690. Its totient is φ = 6666688.

The previous prime is 6666683. The next prime is 6666719. The reversal of 6666689 is 9866666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4000000 + 2666689 = 2000^2 + 1633^2 .

It is a cyclic number.

It is not a de Polignac number, because 6666689 - 2²⁰ = 5618113 is a prime.

It is a Chen prime.

It is a plaindrome in base 10.

It is not a weakly prime, because it can be changed into another prime (6666683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3333344 + 3333345.

It is an arithmetic number, because the mean of its divisors is an integer number (3333345).

Almost surely, 2^6666689 is an apocalyptic number.

It is an amenable number.

6666689 is a deficient number, since it is larger than the sum of its proper divisors (1).

6666689 is an equidigital number, since it uses as much as digits as its factorization.

6666689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 559872, while the sum is 47.

The square root of 6666689 is about 2581.9932222994. The cubic root of 6666689 is about 188.2074159407.

The spelling of 6666689 in words is "six million, six hundred sixty-six thousand, six hundred eighty-nine".