666689989 has 8 divisors (see below), whose sum is σ = 763344128. Its totient is φ = 570389040.

The previous prime is 666689977. The next prime is 666690007. The reversal of 666689989 is 989986666.

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 666689989 - 2⁵ = 666689957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666689189) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 84237 + ... + 91810.

It is an arithmetic number, because the mean of its divisors is an integer number (95418016).

Almost surely, 2^666689989 is an apocalyptic number.

It is an amenable number.

666689989 is a deficient number, since it is larger than the sum of its proper divisors (96654139).

666689989 is a wasteful number, since it uses less digits than its factorization.

666689989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176595.

The product of its digits is 60466176, while the sum is 67.

The square root of 666689989 is about 25820.3406058092. The cubic root of 666689989 is about 873.5906515849.

The spelling of 666689989 in words is "six hundred sixty-six million, six hundred eighty-nine thousand, nine hundred eighty-nine".