128739 has 8 divisors (see below), whose sum is σ = 184912. Its totient is φ = 79200.

The previous prime is 128717. The next prime is 128747. The reversal of 128739 is 937821.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 128739 - 2⁸ = 128483 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128749) 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, 1612 + ... + 1689.

It is an arithmetic number, because the mean of its divisors is an integer number (23114).

2¹²⁸⁷³⁹ is an apocalyptic number.

128739 is a deficient number, since it is larger than the sum of its proper divisors (56173).

128739 is a wasteful number, since it uses less digits than its factorization.

128739 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3317.

The product of its digits is 3024, while the sum is 30.

The square root of 128739 is about 358.8021739065. The cubic root of 128739 is about 50.4936436139.

It can be divided in two parts, 1287 and 39, that added together give a triangular number (1326 = T₅₁).

The spelling of 128739 in words is "one hundred twenty-eight thousand, seven hundred thirty-nine".