128328421 has 16 divisors (see below), whose sum is σ = 140474880. Its totient is φ = 116524800.

The previous prime is 128328373. The next prime is 128328449. The reversal of 128328421 is 124823821.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 128328421 - 2¹⁵ = 128295653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128320421) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 319821 + ... + 320221.

It is an arithmetic number, because the mean of its divisors is an integer number (8779680).

Almost surely, 2^128328421 is an apocalyptic number.

It is an amenable number.

128328421 is a deficient number, since it is larger than the sum of its proper divisors (12146459).

128328421 is a wasteful number, since it uses less digits than its factorization.

128328421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 756.

The product of its digits is 6144, while the sum is 31.

The square root of 128328421 is about 11328.2134955164. The cubic root of 128328421 is about 504.3990773956.

The spelling of 128328421 in words is "one hundred twenty-eight million, three hundred twenty-eight thousand, four hundred twenty-one".