128942389 has 4 divisors (see below), whose sum is σ = 129301920. Its totient is φ = 128582860.

The previous prime is 128942353. The next prime is 128942419. The reversal of 128942389 is 983249821.

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.

It is a cyclic number.

It is not a de Polignac number, because 128942389 - 2¹¹ = 128940341 is a prime.

It is a super-2 number, since 2×128942389² = 33252279362054642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128942329) 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, 179227 + ... + 179944.

It is an arithmetic number, because the mean of its divisors is an integer number (32325480).

Almost surely, 2^128942389 is an apocalyptic number.

It is an amenable number.

128942389 is a deficient number, since it is larger than the sum of its proper divisors (359531).

128942389 is an equidigital number, since it uses as much as digits as its factorization.

128942389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 359530.

The product of its digits is 248832, while the sum is 46.

The square root of 128942389 is about 11355.2802255162. The cubic root of 128942389 is about 505.2022050754.

The spelling of 128942389 in words is "one hundred twenty-eight million, nine hundred forty-two thousand, three hundred eighty-nine".