393918937 has 2 divisors, whose sum is σ = 393918938. Its totient is φ = 393918936.

The previous prime is 393918859. The next prime is 393918961. The reversal of 393918937 is 739819393.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 213715161 + 180203776 = 14619^2 + 13424^2 .

It is an emirp because it is prime and its reverse (739819393) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 393918937 - 2¹⁹ = 393394649 is a prime.

It is not a weakly prime, because it can be changed into another prime (393918997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 196959468 + 196959469.

It is an arithmetic number, because the mean of its divisors is an integer number (196959469).

Almost surely, 2^393918937 is an apocalyptic number.

It is an amenable number.

393918937 is a deficient number, since it is larger than the sum of its proper divisors (1).

393918937 is an equidigital number, since it uses as much as digits as its factorization.

393918937 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1102248, while the sum is 52.

The square root of 393918937 is about 19847.3911887684. The cubic root of 393918937 is about 733.0534124257.

The spelling of 393918937 in words is "three hundred ninety-three million, nine hundred eighteen thousand, nine hundred thirty-seven".