66646689 has 16 divisors (see below), whose sum is σ = 93153984. Its totient is φ = 42336000.

The previous prime is 66646687. The next prime is 66646703. The reversal of 66646689 is 98664666.

It is not a de Polignac number, because 66646689 - 2¹ = 66646687 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66646687) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1012 + ... + 11589.

It is an arithmetic number, because the mean of its divisors is an integer number (5822124).

Almost surely, 2^66646689 is an apocalyptic number.

It is an amenable number.

66646689 is a deficient number, since it is larger than the sum of its proper divisors (26507295).

66646689 is a wasteful number, since it uses less digits than its factorization.

66646689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12688.

The product of its digits is 2239488, while the sum is 51.

The square root of 66646689 is about 8163.7423403731. The cubic root of 66646689 is about 405.4396262571.

The spelling of 66646689 in words is "sixty-six million, six hundred forty-six thousand, six hundred eighty-nine".