394947391 has 2 divisors, whose sum is σ = 394947392. Its totient is φ = 394947390.

The previous prime is 394947353. The next prime is 394947403. The reversal of 394947391 is 193749493.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 394947391 - 2⁷ = 394947263 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (394947331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 197473695 + 197473696.

It is an arithmetic number, because the mean of its divisors is an integer number (197473696).

Almost surely, 2^394947391 is an apocalyptic number.

394947391 is a deficient number, since it is larger than the sum of its proper divisors (1).

394947391 is an equidigital number, since it uses as much as digits as its factorization.

394947391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 734832, while the sum is 49.

The square root of 394947391 is about 19873.2833472479. The cubic root of 394947391 is about 733.6908164553.

The spelling of 394947391 in words is "three hundred ninety-four million, nine hundred forty-seven thousand, three hundred ninety-one".