128840017 has 4 divisors (see below), whose sum is σ = 128862720. Its totient is φ = 128817316.

The previous prime is 128840003. The next prime is 128840021. The reversal of 128840017 is 710048821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 128840017 - 2¹⁹ = 128315729 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128840027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5568 + ... + 16990.

It is an arithmetic number, because the mean of its divisors is an integer number (32215680).

Almost surely, 2^128840017 is an apocalyptic number.

It is an amenable number.

128840017 is a deficient number, since it is larger than the sum of its proper divisors (22703).

128840017 is a wasteful number, since it uses less digits than its factorization.

128840017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22702.

The product of its (nonzero) digits is 3584, while the sum is 31.

The square root of 128840017 is about 11350.7716477780. The cubic root of 128840017 is about 505.0684702769.

Adding to 128840017 its reverse (710048821), we get a palindrome (838888838).

The spelling of 128840017 in words is "one hundred twenty-eight million, eight hundred forty thousand, seventeen".