393856481 has 2 divisors, whose sum is σ = 393856482. Its totient is φ = 393856480.

The previous prime is 393856403. The next prime is 393856487. The reversal of 393856481 is 184658393.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 227859025 + 165997456 = 15095^2 + 12884^2 .

It is an emirp because it is prime and its reverse (184658393) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 393856481 - 2¹⁸ = 393594337 is a prime.

It is a super-2 number, since 2×393856481² = 310245855251406722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (393856487) 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, 196928240 + 196928241.

It is an arithmetic number, because the mean of its divisors is an integer number (196928241).

Almost surely, 2^393856481 is an apocalyptic number.

It is an amenable number.

393856481 is a deficient number, since it is larger than the sum of its proper divisors (1).

393856481 is an equidigital number, since it uses as much as digits as its factorization.

393856481 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 622080, while the sum is 47.

The square root of 393856481 is about 19845.8177206181. The cubic root of 393856481 is about 733.0146684105.

The spelling of 393856481 in words is "three hundred ninety-three million, eight hundred fifty-six thousand, four hundred eighty-one".