394297221 has 4 divisors (see below), whose sum is σ = 525729632. Its totient is φ = 262864812.

The previous prime is 394297217. The next prime is 394297243. The reversal of 394297221 is 122792493.

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: 122792493 = 3 ⋅40930831.

It is not a de Polignac number, because 394297221 - 2² = 394297217 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 394297221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (394297261) 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, 65716201 + ... + 65716206.

It is an arithmetic number, because the mean of its divisors is an integer number (131432408).

Almost surely, 2^394297221 is an apocalyptic number.

It is an amenable number.

394297221 is a deficient number, since it is larger than the sum of its proper divisors (131432411).

394297221 is a wasteful number, since it uses less digits than its factorization.

394297221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131432410.

The product of its digits is 54432, while the sum is 39.

The square root of 394297221 is about 19856.9187186733. The cubic root of 394297221 is about 733.2879900109.

The spelling of 394297221 in words is "three hundred ninety-four million, two hundred ninety-seven thousand, two hundred twenty-one".