128217789 has 16 divisors (see below), whose sum is σ = 217088640. Its totient is φ = 73267200.

The previous prime is 128217773. The next prime is 128217809. The reversal of 128217789 is 987712821.

It is not a de Polignac number, because 128217789 - 2⁴ = 128217773 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128217389) 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, 339012 + ... + 339389.

It is an arithmetic number, because the mean of its divisors is an integer number (13568040).

Almost surely, 2^128217789 is an apocalyptic number.

It is an amenable number.

128217789 is a deficient number, since it is larger than the sum of its proper divisors (88870851).

128217789 is an equidigital number, since it uses as much as digits as its factorization.

128217789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 678417 (or 678411 counting only the distinct ones).

The product of its digits is 112896, while the sum is 45.

The square root of 128217789 is about 11323.3294132071. The cubic root of 128217789 is about 504.2540881515.

The spelling of 128217789 in words is "one hundred twenty-eight million, two hundred seventeen thousand, seven hundred eighty-nine".