391678057 has 2 divisors, whose sum is σ = 391678058. Its totient is φ = 391678056.

The previous prime is 391678019. The next prime is 391678097. The reversal of 391678057 is 750876193.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 337861161 + 53816896 = 18381^2 + 7336^2 .

It is a cyclic number.

It is not a de Polignac number, because 391678057 - 2²³ = 383289449 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 391677998 and 391678016.

It is not a weakly prime, because it can be changed into another prime (391678097) 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, 195839028 + 195839029.

It is an arithmetic number, because the mean of its divisors is an integer number (195839029).

Almost surely, 2^391678057 is an apocalyptic number.

It is an amenable number.

391678057 is a deficient number, since it is larger than the sum of its proper divisors (1).

391678057 is an equidigital number, since it uses as much as digits as its factorization.

391678057 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 317520, while the sum is 46.

The square root of 391678057 is about 19790.8579147040. The cubic root of 391678057 is about 731.6607320522.

The spelling of 391678057 in words is "three hundred ninety-one million, six hundred seventy-eight thousand, fifty-seven".