391648841 has 2 divisors, whose sum is σ = 391648842. Its totient is φ = 391648840.

The previous prime is 391648819. The next prime is 391648867. The reversal of 391648841 is 148846193.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 292546816 + 99102025 = 17104^2 + 9955^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-391648841 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 391648792 and 391648801.

It is not a weakly prime, because it can be changed into another prime (391648801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195824420 + 195824421.

It is an arithmetic number, because the mean of its divisors is an integer number (195824421).

Almost surely, 2^391648841 is an apocalyptic number.

It is an amenable number.

391648841 is a deficient number, since it is larger than the sum of its proper divisors (1).

391648841 is an equidigital number, since it uses as much as digits as its factorization.

391648841 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 165888, while the sum is 44.

The square root of 391648841 is about 19790.1197823560. The cubic root of 391648841 is about 731.6425396183.

The spelling of 391648841 in words is "three hundred ninety-one million, six hundred forty-eight thousand, eight hundred forty-one".