391394947 has 2 divisors, whose sum is σ = 391394948. Its totient is φ = 391394946.

The previous prime is 391394923. The next prime is 391394963. The reversal of 391394947 is 749493193.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 391394947 - 2⁷ = 391394819 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 391394947.

It is not a weakly prime, because it can be changed into another prime (391397947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195697473 + 195697474.

It is an arithmetic number, because the mean of its divisors is an integer number (195697474).

Almost surely, 2^391394947 is an apocalyptic number.

391394947 is a deficient number, since it is larger than the sum of its proper divisors (1).

391394947 is an equidigital number, since it uses as much as digits as its factorization.

391394947 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 391394947 is about 19783.7040768406. The cubic root of 391394947 is about 731.4844049266.

The spelling of 391394947 in words is "three hundred ninety-one million, three hundred ninety-four thousand, nine hundred forty-seven".