393744641 has 2 divisors, whose sum is σ = 393744642. Its totient is φ = 393744640.

The previous prime is 393744623. The next prime is 393744643. The reversal of 393744641 is 146447393.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 354004225 + 39740416 = 18815^2 + 6304^2 .

It is an emirp because it is prime and its reverse (146447393) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-393744641 is a prime.

Together with 393744643, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (393744643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 196872320 + 196872321.

It is an arithmetic number, because the mean of its divisors is an integer number (196872321).

Almost surely, 2^393744641 is an apocalyptic number.

It is an amenable number.

393744641 is a deficient number, since it is larger than the sum of its proper divisors (1).

393744641 is an equidigital number, since it uses as much as digits as its factorization.

393744641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 217728, while the sum is 41.

The square root of 393744641 is about 19842.9997984176. Note that the first 3 decimals coincide. The cubic root of 393744641 is about 732.9452792418.

The spelling of 393744641 in words is "three hundred ninety-three million, seven hundred forty-four thousand, six hundred forty-one".