391396877 has 2 divisors, whose sum is σ = 391396878. Its totient is φ = 391396876.

The previous prime is 391396867. The next prime is 391396897. The reversal of 391396877 is 778693193.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 199685161 + 191711716 = 14131^2 + 13846^2 .

It is a cyclic number.

It is not a de Polignac number, because 391396877 - 2⁴ = 391396861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (391396867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195698438 + 195698439.

It is an arithmetic number, because the mean of its divisors is an integer number (195698439).

Almost surely, 2^391396877 is an apocalyptic number.

It is an amenable number.

391396877 is a deficient number, since it is larger than the sum of its proper divisors (1).

391396877 is an equidigital number, since it uses as much as digits as its factorization.

391396877 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1714608, while the sum is 53.

The square root of 391396877 is about 19783.7528542994. The cubic root of 391396877 is about 731.4856072608.

The spelling of 391396877 in words is "three hundred ninety-one million, three hundred ninety-six thousand, eight hundred seventy-seven".