394128321 has 4 divisors (see below), whose sum is σ = 525504432. Its totient is φ = 262752212.

The previous prime is 394128311. The next prime is 394128337. The reversal of 394128321 is 123821493.

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 394128321 - 2⁶ = 394128257 is a prime.

It is not an unprimeable number, because it can be changed into a prime (394128311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65688051 + ... + 65688056.

It is an arithmetic number, because the mean of its divisors is an integer number (131376108).

Almost surely, 2^394128321 is an apocalyptic number.

It is an amenable number.

394128321 is a deficient number, since it is larger than the sum of its proper divisors (131376111).

394128321 is a wasteful number, since it uses less digits than its factorization.

394128321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131376110.

The product of its digits is 10368, while the sum is 33.

The square root of 394128321 is about 19852.6653374301. The cubic root of 394128321 is about 733.1832720271.

The spelling of 394128321 in words is "three hundred ninety-four million, one hundred twenty-eight thousand, three hundred twenty-one".