666668889 has 24 divisors (see below), whose sum is σ = 1020943872. Its totient is φ = 417755520.

The previous prime is 666668851. The next prime is 666668909. The reversal of 666668889 is 988866666.

It is not a de Polignac number, because 666668889 - 2¹¹ = 666666841 is a prime.

It is a Curzon number.

It is a plaindrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (666668389) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 136992 + ... + 141774.

It is an arithmetic number, because the mean of its divisors is an integer number (42539328).

Almost surely, 2^666668889 is an apocalyptic number.

It is an amenable number.

666668889 is a deficient number, since it is larger than the sum of its proper divisors (354274983).

666668889 is a wasteful number, since it uses less digits than its factorization.

666668889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5717 (or 5714 counting only the distinct ones).

The product of its digits is 35831808, while the sum is 63.

The square root of 666668889 is about 25819.9320099802. The cubic root of 666668889 is about 873.5814354287.

The spelling of 666668889 in words is "six hundred sixty-six million, six hundred sixty-eight thousand, eight hundred eighty-nine".