66128789 has 8 divisors (see below), whose sum is σ = 67830912. Its totient is φ = 64443600.

The previous prime is 66128747. The next prime is 66128791. The reversal of 66128789 is 98782166.

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 66128789 - 2¹⁶ = 66063253 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66128719) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3872 + ... + 12134.

It is an arithmetic number, because the mean of its divisors is an integer number (8478864).

Almost surely, 2^66128789 is an apocalyptic number.

It is an amenable number.

66128789 is a deficient number, since it is larger than the sum of its proper divisors (1702123).

66128789 is a wasteful number, since it uses less digits than its factorization.

66128789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8467.

The product of its digits is 290304, while the sum is 47.

The square root of 66128789 is about 8131.9609566205. The cubic root of 66128789 is about 404.3866935218.

The spelling of 66128789 in words is "sixty-six million, one hundred twenty-eight thousand, seven hundred eighty-nine".