391948477 has 2 divisors, whose sum is σ = 391948478. Its totient is φ = 391948476.

The previous prime is 391948439. The next prime is 391948489. The reversal of 391948477 is 774849193.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 380211001 + 11737476 = 19499^2 + 3426^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-391948477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (391148477) 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, 195974238 + 195974239.

It is an arithmetic number, because the mean of its divisors is an integer number (195974239).

Almost surely, 2^391948477 is an apocalyptic number.

It is an amenable number.

391948477 is a deficient number, since it is larger than the sum of its proper divisors (1).

391948477 is an equidigital number, since it uses as much as digits as its factorization.

391948477 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1524096, while the sum is 52.

The square root of 391948477 is about 19797.6886782271. The cubic root of 391948477 is about 731.8290762446.

The spelling of 391948477 in words is "three hundred ninety-one million, nine hundred forty-eight thousand, four hundred seventy-seven".