128769 has 4 divisors (see below), whose sum is σ = 171696. Its totient is φ = 85844.

The previous prime is 128767. The next prime is 128813. The reversal of 128769 is 967821.

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 an emirpimes, since its reverse is a distinct semiprime: 967821 = 3 ⋅322607.

It is a cyclic number.

It is not a de Polignac number, because 128769 - 2¹ = 128767 is a prime.

It is a super-2 number, since 2×128769² = 33162910722, which contains 22 as substring.

It is a D-number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (128761) 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, 21459 + ... + 21464.

It is an arithmetic number, because the mean of its divisors is an integer number (42924).

2¹²⁸⁷⁶⁹ is an apocalyptic number.

It is an amenable number.

128769 is a deficient number, since it is larger than the sum of its proper divisors (42927).

128769 is an equidigital number, since it uses as much as digits as its factorization.

128769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42926.

The product of its digits is 6048, while the sum is 33.

The square root of 128769 is about 358.8439772380. The cubic root of 128769 is about 50.4975654808.

The spelling of 128769 in words is "one hundred twenty-eight thousand, seven hundred sixty-nine".