397840393 has 2 divisors, whose sum is σ = 397840394. Its totient is φ = 397840392.

The previous prime is 397840367. The next prime is 397840403. The reversal of 397840393 is 393048793.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 238146624 + 159693769 = 15432^2 + 12637^2 .

It is an emirp because it is prime and its reverse (393048793) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-397840393 is a prime.

It is not a weakly prime, because it can be changed into another prime (397843393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 198920196 + 198920197.

It is an arithmetic number, because the mean of its divisors is an integer number (198920197).

Almost surely, 2^397840393 is an apocalyptic number.

It is an amenable number.

397840393 is a deficient number, since it is larger than the sum of its proper divisors (1).

397840393 is an equidigital number, since it uses as much as digits as its factorization.

397840393 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 489888, while the sum is 46.

The square root of 397840393 is about 19945.9367541362. The cubic root of 397840393 is about 735.4778961251.

The spelling of 397840393 in words is "three hundred ninety-seven million, eight hundred forty thousand, three hundred ninety-three".