91006781779 has 2 divisors, whose sum is σ = 91006781780. Its totient is φ = 91006781778.

The previous prime is 91006781753. The next prime is 91006781783. The reversal of 91006781779 is 97718760019.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91006781779 is a prime.

It is not a weakly prime, because it can be changed into another prime (91006781729) 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, 45503390889 + 45503390890.

It is an arithmetic number, because the mean of its divisors is an integer number (45503390890).

Almost surely, 2^91006781779 is an apocalyptic number.

91006781779 is a deficient number, since it is larger than the sum of its proper divisors (1).

91006781779 is an equidigital number, since it uses as much as digits as its factorization.

91006781779 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1333584, while the sum is 55.

The spelling of 91006781779 in words is "ninety-one billion, six million, seven hundred eighty-one thousand, seven hundred seventy-nine".