91329005821 has 2 divisors, whose sum is σ = 91329005822. Its totient is φ = 91329005820.

The previous prime is 91329005767. The next prime is 91329005861. The reversal of 91329005821 is 12850092319.

It is an a-pointer prime, because the next prime (91329005861) can be obtained adding 91329005821 to its sum of digits (40).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 83177444025 + 8151561796 = 288405^2 + 90286^2 .

It is an emirp because it is prime and its reverse (12850092319) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91329005821 - 2⁹ = 91329005309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91329005861) 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, 45664502910 + 45664502911.

It is an arithmetic number, because the mean of its divisors is an integer number (45664502911).

Almost surely, 2^91329005821 is an apocalyptic number.

It is an amenable number.

91329005821 is a deficient number, since it is larger than the sum of its proper divisors (1).

91329005821 is an equidigital number, since it uses as much as digits as its factorization.

91329005821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 38880, while the sum is 40.

The spelling of 91329005821 in words is "ninety-one billion, three hundred twenty-nine million, five thousand, eight hundred twenty-one".