394338721 has 6 divisors (see below), whose sum is σ = 458720610. Its totient is φ = 338004576.

The previous prime is 394338701. The next prime is 394338743. The reversal of 394338721 is 127833493.

It can be written as a sum of positive squares in only one way, i.e., 390497121 + 3841600 = 19761^2 + 1960^2 .

It is not a de Polignac number, because 394338721 - 2⁹ = 394338209 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 (394338701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4023816 + ... + 4023913.

It is an arithmetic number, because the mean of its divisors is an integer number (76453435).

Almost surely, 2^394338721 is an apocalyptic number.

It is an amenable number.

394338721 is a deficient number, since it is larger than the sum of its proper divisors (64381889).

394338721 is an equidigital number, since it uses as much as digits as its factorization.

394338721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8047743 (or 8047736 counting only the distinct ones).

The product of its digits is 108864, while the sum is 40.

The square root of 394338721 is about 19857.9636670027. The cubic root of 394338721 is about 733.3137154302.

The spelling of 394338721 in words is "three hundred ninety-four million, three hundred thirty-eight thousand, seven hundred twenty-one".