384388021 has 2 divisors, whose sum is σ = 384388022. Its totient is φ = 384388020.

The previous prime is 384388019. The next prime is 384388027. The reversal of 384388021 is 120883483.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 230280625 + 154107396 = 15175^2 + 12414^2 .

It is a cyclic number.

It is not a de Polignac number, because 384388021 - 2¹ = 384388019 is a prime.

Together with 384388019, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (384388027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 192194010 + 192194011.

It is an arithmetic number, because the mean of its divisors is an integer number (192194011).

Almost surely, 2^384388021 is an apocalyptic number.

It is an amenable number.

384388021 is a deficient number, since it is larger than the sum of its proper divisors (1).

384388021 is an equidigital number, since it uses as much as digits as its factorization.

384388021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36864, while the sum is 37.

The square root of 384388021 is about 19605.8159993406. The cubic root of 384388021 is about 727.0929744921.

The spelling of 384388021 in words is "three hundred eighty-four million, three hundred eighty-eight thousand, twenty-one".