393738221 has 2 divisors, whose sum is σ = 393738222. Its totient is φ = 393738220.

The previous prime is 393738209. The next prime is 393738253. The reversal of 393738221 is 122837393.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 312936100 + 80802121 = 17690^2 + 8989^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-393738221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (393738271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 196869110 + 196869111.

It is an arithmetic number, because the mean of its divisors is an integer number (196869111).

Almost surely, 2^393738221 is an apocalyptic number.

It is an amenable number.

393738221 is a deficient number, since it is larger than the sum of its proper divisors (1).

393738221 is an equidigital number, since it uses as much as digits as its factorization.

393738221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 54432, while the sum is 38.

The square root of 393738221 is about 19842.8380278628. The cubic root of 393738221 is about 732.9412956665.

The spelling of 393738221 in words is "three hundred ninety-three million, seven hundred thirty-eight thousand, two hundred twenty-one".