393918997 has 2 divisors, whose sum is σ = 393918998. Its totient is φ = 393918996.

The previous prime is 393918971. The next prime is 393919067. The reversal of 393918997 is 799819393.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 393387556 + 531441 = 19834^2 + 729^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-393918997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (393918937) 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, 196959498 + 196959499.

It is an arithmetic number, because the mean of its divisors is an integer number (196959499).

Almost surely, 2^393918997 is an apocalyptic number.

It is an amenable number.

393918997 is a deficient number, since it is larger than the sum of its proper divisors (1).

393918997 is an equidigital number, since it uses as much as digits as its factorization.

393918997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3306744, while the sum is 58.

The square root of 393918997 is about 19847.3927003020. The cubic root of 393918997 is about 733.0534496442.

The spelling of 393918997 in words is "three hundred ninety-three million, nine hundred eighteen thousand, nine hundred ninety-seven".