393879221 has 4 divisors (see below), whose sum is σ = 400555200. Its totient is φ = 387203244.

The previous prime is 393879217. The next prime is 393879229. The reversal of 393879221 is 122978393.

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.

It is a cyclic number.

It is not a de Polignac number, because 393879221 - 2² = 393879217 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (393879229) 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, 3337901 + ... + 3338018.

It is an arithmetic number, because the mean of its divisors is an integer number (100138800).

Almost surely, 2^393879221 is an apocalyptic number.

It is an amenable number.

393879221 is a deficient number, since it is larger than the sum of its proper divisors (6675979).

393879221 is an equidigital number, since it uses as much as digits as its factorization.

393879221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6675978.

The product of its digits is 163296, while the sum is 44.

The square root of 393879221 is about 19846.3906290287. The cubic root of 393879221 is about 733.0287754381.

The spelling of 393879221 in words is "three hundred ninety-three million, eight hundred seventy-nine thousand, two hundred twenty-one".