391749432779 has 2 divisors, whose sum is σ = 391749432780. Its totient is φ = 391749432778.

The previous prime is 391749432761. The next prime is 391749432817. The reversal of 391749432779 is 977234947193.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 391749432779 - 2¹² = 391749428683 is a prime.

It is not a weakly prime, because it can be changed into another prime (391749432719) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195874716389 + 195874716390.

It is an arithmetic number, because the mean of its divisors is an integer number (195874716390).

Almost surely, 2^391749432779 is an apocalyptic number.

391749432779 is a deficient number, since it is larger than the sum of its proper divisors (1).

391749432779 is an equidigital number, since it uses as much as digits as its factorization.

391749432779 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72013536, while the sum is 65.

The spelling of 391749432779 in words is "three hundred ninety-one billion, seven hundred forty-nine million, four hundred thirty-two thousand, seven hundred seventy-nine".