128423261 has 4 divisors (see below), whose sum is σ = 135182400. Its totient is φ = 121664124.

The previous prime is 128423233. The next prime is 128423291. The reversal of 128423261 is 162324821.

It is a happy number.

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: 162324821 = 1451 ⋅111871.

It is a cyclic number.

It is not a de Polignac number, because 128423261 - 2¹⁴ = 128406877 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128423201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3379541 + ... + 3379578.

It is an arithmetic number, because the mean of its divisors is an integer number (33795600).

Almost surely, 2^128423261 is an apocalyptic number.

It is an amenable number.

128423261 is a deficient number, since it is larger than the sum of its proper divisors (6759139).

128423261 is an equidigital number, since it uses as much as digits as its factorization.

128423261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6759138.

The product of its digits is 4608, while the sum is 29.

The square root of 128423261 is about 11332.3987310719. The cubic root of 128423261 is about 504.5233040436.

The spelling of 128423261 in words is "one hundred twenty-eight million, four hundred twenty-three thousand, two hundred sixty-one".