128817 has 16 divisors (see below), whose sum is σ = 206080. Its totient is φ = 79056.

The previous prime is 128813. The next prime is 128819. The reversal of 128817 is 718821.

It is not a de Polignac number, because 128817 - 2² = 128813 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 168 + ... + 534.

It is an arithmetic number, because the mean of its divisors is an integer number (12880).

2¹²⁸⁸¹⁷ is an apocalyptic number.

It is an amenable number.

128817 is a deficient number, since it is larger than the sum of its proper divisors (77263).

128817 is a wasteful number, since it uses less digits than its factorization.

128817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 389 (or 383 counting only the distinct ones).

The product of its digits is 896, while the sum is 27.

The square root of 128817 is about 358.9108524411. The cubic root of 128817 is about 50.5038392010.

The spelling of 128817 in words is "one hundred twenty-eight thousand, eight hundred seventeen".